Cheatsheets on Linuxize

npm Cheatsheet

hello@linuxize.com (Linuxize) — Fri, 05 Jun 2026 10:20:00 +0200

Project Setup

Create and inspect project metadata.

Command	Description
`npm init`	Create package.json interactively
`npm init -y`	Create package.json with defaults
`npm pkg get name`	Print package name
`npm pkg set scripts.start="node index.js"`	Add or update a script
`npm pkg delete scripts.old`	Remove a package.json field

Install Dependencies

Add project, development, and global packages.

Command	Description
`npm install`	Install project dependencies
`npm install package`	Install and save dependency
`npm install -D package`	Install development dependency
`npm install -g package`	Install global CLI package
`npm install package@1.2.3`	Install a specific version
`npm install package@latest`	Install latest published version
`npm install --no-save package`	Install without saving

Clean Installs

Reproduce dependency trees from lock files.

Command	Description
`npm ci`	Clean install from package-lock.json
`npm ci --omit=dev`	Install production dependencies only
`npm install --omit=dev`	Skip development dependencies
`npm install --package-lock-only`	Update lock file only
`npm install --ignore-scripts`	Install without lifecycle scripts

Versions and Updates

Check outdated packages and update dependency ranges.

Command	Description
`npm outdated`	Show packages with newer versions
`npm update`	Update within package.json ranges
`npm update package`	Update one package
`npm view package version`	Show latest package version
`npm view package versions`	List published versions
`npm version patch`	Bump package patch version
`npm version minor`	Bump package minor version

Remove and Clean

Uninstall packages and clear generated files.

Command	Description
`npm uninstall package`	Remove dependency
`npm uninstall -D package`	Remove development dependency
`npm uninstall -g package`	Remove global package
`npm prune`	Remove extraneous packages
`npm dedupe`	Reduce duplicate dependencies
`npm cache verify`	Verify npm cache
`npm cache clean --force`	Clear npm cache

Scripts and Execution

Run package scripts and one-off tools.

Command	Description
`npm run`	List available scripts
`npm run script`	Run a named script
`npm start`	Run the start script
`npm test`	Run the test script
`npm run build -- --watch`	Pass args to script
`npx package`	Run package binary once
`npm create vite@latest app`	Run create package

Inspect Packages

List dependencies and package metadata.

Command	Description
`npm list`	List direct dependencies
`npm list --all`	List full dependency tree
`npm list -g --depth=0`	List global packages
`npm explain package`	Explain why package is installed
`npm root`	Show local node_modules path
`npm root -g`	Show global node_modules path

Configuration

View and change npm settings.

Command	Description
`npm config list`	Show current config
`npm config get prefix`	Show global install prefix
`npm config set prefix ~/.npm-global`	Set global install prefix
`npm config get registry`	Show registry URL
`npm config set registry url`	Set registry URL
`npm whoami`	Show logged-in npm user
`npm login`	Log in to npm registry

Security and Audit

Check dependency risks and funding metadata.

Command	Description
`npm audit`	Scan dependencies for advisories
`npm audit fix`	Apply compatible security fixes
`npm audit --omit=dev`	Audit production dependencies
`npm fund`	Show funding links
`npm doctor`	Check npm environment
`npm ping`	Test registry connection

Use these references for Node.js and package workflows.

Guide	Description
`npm Command`	Full npm tutorial with examples
`Install Node.js on Ubuntu 26.04`	Install Node.js and npm
`Install Yarn on Ubuntu 20.04`	Alternative package manager

Podman Cheatsheet

hello@linuxize.com (Linuxize) — Wed, 03 Jun 2026 14:15:00 +0200

Container Lifecycle

Create, start, stop, and remove containers.

Command	Description
`podman run image`	Create and start a container
`podman run -d image`	Run container in background
`podman run -it image sh`	Run with an interactive shell
`podman run --name web image`	Run with a custom name
`podman run -p 8080:80 image`	Map host port to container port
`podman run -v /host:/container image`	Bind mount a host path
`podman start container`	Start a stopped container
`podman stop container`	Gracefully stop a container
`podman restart container`	Restart a container
`podman rm container`	Remove a stopped container
`podman rm -f container`	Force remove a running container
`podman kill container`	Kill a container with SIGKILL
`podman pause container`	Pause a running container
`podman unpause container`	Resume a paused container

Container Inspection

List containers, inspect state, and watch resource use.

Command	Description
`podman ps`	List running containers
`podman ps -a`	List all containers
`podman ps -q`	Show only container IDs
`podman inspect container`	Show detailed JSON info
`podman inspect --format '{{.State.Status}}' container`	Print one field
`podman top container`	List processes in a container
`podman stats`	Show live resource usage
`podman stats --no-stream`	Print one usage snapshot
`podman port container`	Show port mappings
`podman diff container`	Show filesystem changes

Logs

Read and follow container logs.

Command	Description
`podman logs container`	View container logs
`podman logs -f container`	Follow live logs
`podman logs --tail 50 container`	Show the last 50 lines
`podman logs -t container`	Add timestamps
`podman logs --since 10m container`	Show recent logs
`podman logs --until 2026-06-03T12:00:00 container`	Stop at a time
`journalctl --user -u name.service`	View logs for a user service
`sudo journalctl -u name.service`	View logs for a system service

Images and Builds

Pull, build, tag, and manage images. Podman accepts Dockerfiles and Containerfiles.

Command	Description
`podman pull image:tag`	Pull image from a registry
`podman pull docker.io/library/nginx`	Pull with a full image name
`podman push image:tag`	Push image to a registry
`podman build -t name .`	Build image from Dockerfile
`podman build -f Containerfile .`	Build with a custom file
`podman images`	List local images
`podman rmi image`	Remove an image
`podman tag source target:tag`	Tag an image
`podman save image > image.tar`	Save image to tar archive
`podman load < image.tar`	Load image from tar archive
`podman history image`	Show image layer history

Exec and Copy

Run commands inside containers and copy files.

Command	Description
`podman exec -it container sh`	Open shell in container
`podman exec -it container bash`	Open Bash if installed
`podman exec container command`	Run command in container
`podman exec -u root container command`	Run as a specific user
`podman cp ./file container:/path/`	Copy file into container
`podman cp container:/path/file ./`	Copy file from container
`podman attach container`	Attach to main process
`podman wait container`	Wait for container to stop

Volumes

Manage persistent container data.

Command	Description
`podman volume create data`	Create a named volume
`podman volume ls`	List volumes
`podman volume inspect data`	Show volume details
`podman volume rm data`	Remove a volume
`podman volume prune`	Remove unused volumes
`podman run -v data:/data image`	Mount named volume
`podman run -v /host:/data image`	Bind mount host directory
`podman run -v /host:/data:Z image`	Bind mount with SELinux relabeling
`podman run --tmpfs /tmp image`	Mount tmpfs in a container

Networks

Create networks and connect containers.

Command	Description
`podman network create net`	Create a network
`podman network ls`	List networks
`podman network inspect net`	Show network details
`podman network rm net`	Remove a network
`podman network connect net container`	Connect container to network
`podman network disconnect net container`	Disconnect from network
`podman run --network net image`	Run container on network
`podman run --network host image`	Use host networking
`podman run --network none image`	Disable networking

Pods

Run groups of containers that share a network namespace.

Command	Description
`podman pod create --name app`	Create a pod
`podman pod create --name app -p 8080:80`	Create pod with port mapping
`podman run --pod app image`	Run container in pod
`podman pod ps`	List pods
`podman ps --pod`	Show containers with pod info
`podman pod inspect app`	Show pod details
`podman pod stop app`	Stop all containers in pod
`podman pod start app`	Start pod containers
`podman pod rm app`	Remove a stopped pod
`podman pod rm -f app`	Force remove a pod

Rootless and systemd

Inspect rootless mode and manage Podman with systemd.

Command	Description
`podman info`	Show Podman host configuration
`podman info --format '{{.Host.Security.Rootless}}'`	Check if rootless
`podman system migrate`	Apply user namespace changes
`systemctl --user enable --now podman.socket`	Start user Podman socket
`sudo systemctl enable --now podman.socket`	Start system Podman socket
`sudo loginctl enable-linger $USER`	Keep user services after logout
`systemctl --user daemon-reload`	Reload user units
`systemctl --user status name.service`	Check user service
`sudo systemctl status name.service`	Check system service
`podman auto-update`	Update containers with auto-update labels

Compose

Run Compose projects with Podman.

Command	Description
`podman compose up`	Start Compose project
`podman compose up -d`	Start in background
`podman compose down`	Stop and remove services
`podman compose ps`	List Compose services
`podman compose logs`	View Compose logs
`podman compose exec service sh`	Shell into a service
`podman-compose up -d`	Use podman-compose directly
`export DOCKER_HOST=unix://$XDG_RUNTIME_DIR/podman/podman.sock`	Point Docker Compose at Podman
`docker compose up -d`	Run Docker Compose against Podman socket

System and Cleanup

Check disk usage and remove unused data.

Command	Description
`podman system df`	Show storage usage
`podman system prune`	Remove unused data
`podman system prune --volumes`	Also remove unused volumes
`podman image prune`	Remove dangling images
`podman image prune -a`	Remove unused images
`podman container prune`	Remove stopped containers
`podman volume prune`	Remove unused volumes
`podman network prune`	Remove unused networks
`podman system reset`	Remove all Podman storage

Authenticate and work with container registries.

Command	Description
`podman login docker.io`	Log in to Docker Hub
`podman login registry.example.com`	Log in to private registry
`podman logout docker.io`	Log out from registry
`podman search term`	Search configured registries
`podman pull user/image:tag`	Pull image from registry
`podman push user/image:tag`	Push image to registry
`podman tag image registry/user/image:tag`	Tag image for registry
`podman manifest create name`	Create manifest list
`podman manifest push name destination`	Push manifest list

Docker Compatibility

Use Podman with Docker-style commands and tooling.

Command	Description
`sudo apt install podman-docker`	Install Docker-compatible wrapper
`docker ps`	Run Podman through Docker wrapper
`alias docker=podman`	Add shell alias
`podman --remote ps`	Use remote Podman client
`podman system service --time=0`	Start API service manually
`podman info --format '{{.Host.RemoteSocket.Path}}'`	Show remote socket path
`podman run -d -p 8080:80 nginx`	Docker-like run command

dpkg Cheatsheet

hello@linuxize.com (Linuxize) — Mon, 01 Jun 2026 13:40:00 +0200

Install and Remove

Work with installed packages and local .deb files.

Command	Description
`sudo dpkg -i package.deb`	Install a local .deb file
`sudo dpkg -i *.deb`	Install multiple .deb files
`sudo dpkg -r package`	Remove package, keep config
`sudo dpkg -P package`	Purge package and config
`sudo dpkg --unpack package.deb`	Unpack without configuring

Query Installed Packages

List packages and inspect installed package metadata.

Command	Description
`dpkg -l`	List installed packages
`dpkg -l 'nginx*'`	Filter packages by pattern
`dpkg -s package`	Show package status
`dpkg --status package`	Same as `dpkg -s`
`dpkg-query -W package`	Show package and version

Package Files

Find installed files and file ownership.

Command	Description
`dpkg -L package`	List files installed by package
`dpkg -S /path/to/file`	Find package owning a file
`dpkg -S '*/bin/curl'`	Search ownership by pattern
`dpkg -L package \| less`	Browse long file lists
`dpkg -V package`	Verify installed package files

Inspect deb Files

Read package archives before installing them.

Command	Description
`dpkg --info package.deb`	Show .deb metadata
`dpkg -I package.deb`	Same as `dpkg --info`
`dpkg --contents package.deb`	List files in .deb
`dpkg -c package.deb`	Same as `dpkg --contents`
`dpkg-deb -f package.deb Version`	Print package version field

Extract deb Files

Unpack archive contents without installing.

Command	Description
`dpkg -x package.deb /tmp/extract`	Extract package files
`dpkg -X package.deb /tmp/extract`	Extract with details
`dpkg -e package.deb /tmp/control`	Extract control files
`dpkg-deb --ctrl-tarfile package.deb`	Print control tar archive
`dpkg-deb --fsys-tarfile package.deb`	Print filesystem tar archive

Package Selections

Export and restore package selection states.

Command	Description
`dpkg --get-selections`	Print package selections
`dpkg --get-selections > packages.txt`	Save selections
`sudo dpkg --set-selections < packages.txt`	Restore selections
`dpkg --get-selections 'nginx*'`	Filter selections
`sudo apt-get dselect-upgrade`	Apply restored selections

Repair and Configure

Resume interrupted installs and fix package state.

Command	Description
`sudo dpkg --configure -a`	Configure pending packages
`sudo dpkg --configure package`	Configure one package
`sudo dpkg -C`	Audit broken packages
`sudo apt install -f`	Fix missing dependencies
`sudo dpkg-reconfigure package`	Re-run package setup

Use these references for package management workflows.

Guide	Description
`dpkg Command in Linux`	Full dpkg tutorial with examples
`Install deb Files on Ubuntu`	Install local .deb files with apt and dpkg
`apt Cheatsheet`	Higher-level package management commands

reboot Cheatsheet

hello@linuxize.com (Linuxize) — Sun, 31 May 2026 13:15:00 +0200

Immediate Reboot

Command	Description
`sudo reboot`	Reboot immediately
`sudo systemctl reboot`	Reboot via systemd
`sudo shutdown -r now`	Reboot immediately via shutdown

systemctl Options

Command	Description
`sudo systemctl reboot --force`	Skip graceful shutdown if unresponsive
`sudo systemctl --no-wall reboot`	Reboot without broadcasting a wall message
`sudo systemctl --message="reason" reboot`	Log a reason in the system journal

Schedule with shutdown -r

Command	Description
`sudo shutdown -r +5`	Reboot in 5 minutes
`sudo shutdown -r 10:00`	Reboot at 10:00
`sudo shutdown -r +10 "message"`	Reboot in 10 minutes with a wall message
`sudo shutdown -r`	Reboot after 1 minute (default)

Cancel and Status

Command	Description
`sudo shutdown -c`	Cancel a scheduled reboot
`last reboot`	Show reboot history
`uptime -s`	Show current boot time
`journalctl --list-boots`	List all boot sessions

ripgrep Cheatsheet

hello@linuxize.com (Linuxize) — Tue, 26 May 2026 10:20:00 +0200

Basic Search

Search files and directories for matching text.

Command	Description
`rg "pattern"`	Search recursively from the current directory
`rg "pattern" file.txt`	Search a single file
`rg "pattern" dir/`	Search a specific directory
`rg "pattern" file1 file2`	Search specific files
`rg --version`	Show the installed ripgrep version

File Type Filters

Limit searches to known file types.

Command	Description
`rg -t py "pattern"`	Search only Python files
`rg -t js "pattern"`	Search only JavaScript files
`rg -t markdown "pattern"`	Search only Markdown files
`rg -T js "pattern"`	Exclude JavaScript files
`rg --type-list`	Show available file type names

Glob Filters

Include or exclude paths with glob patterns.

Command	Description
`rg -g '*.log' "error"`	Search only `.log` files
`rg -g '*.conf' "listen" /etc`	Search matching config files
`rg -g '!*.min.js' "console.log"`	Exclude minified JavaScript files
`rg -g '!node_modules/' "TODO"`	Exclude a directory
`rg -g '*.md' -g '!README.md' "pattern"`	Combine include and exclude globs

Case and Literal Search

Control case matching and regex handling.

Command	Description
`rg -i "warning"`	Case-insensitive search
`rg -S "warning"`	Smart case search
`rg -s "Warning"`	Force case-sensitive search
`rg -F "price[0]"`	Search for a fixed string
`rg -w "id"`	Match whole words only

Counts and File Lists

Summarize matches or print filenames.

Command	Description
`rg -c "error"`	Count matching lines per file
`rg --count-matches "error"`	Count individual matches per file
`rg -l "error"`	List files with matches
`rg --files-without-match "error"`	List files without matches
`rg --stats "error"`	Print search statistics

Context Output

Show lines around each match.

Command	Description
`rg -C 3 "panic"`	Show 3 lines before and after
`rg -A 2 "error"`	Show 2 lines after
`rg -B 2 "error"`	Show 2 lines before
`rg -n "error"`	Show line numbers
`rg -N "error"`	Hide line numbers

Patterns and Regex

Search with multiple patterns and regex features.

Command	Description
`rg -e "error" -e "warning"`	Match either pattern
`rg -e "--force"`	Search for a pattern starting with `-`
`rg 'error\|warning'`	Use regex alternation
`rg '^server'`	Match lines starting with `server`
`rg 'listen$'`	Match lines ending with `listen`

Hidden and Ignored Files

Search paths that rg skips by default.

Command	Description
`rg --hidden "api_key"`	Include hidden files and directories
`rg --no-ignore "TODO"`	Ignore `.gitignore`, `.ignore`, and `.rgignore`
`rg --hidden --no-ignore "password"`	Search hidden and ignored files
`rg -u "pattern"`	Reduce ignore filtering by one level
`rg -uuu "pattern"`	Search almost everything, including binary files

Replacement Preview

Preview changed output without editing files.

Command	Description
`rg "old" -r "new"`	Preview replacing `old` with `new`
`rg '(foo)(bar)' -r '$2$1'`	Reorder capture groups in output
`rg -o 'v[0-9]+\.[0-9]+\.[0-9]+'`	Print only matched version strings
`rg -o -r '$1' 'version = "([^"]+)"'`	Extract a captured value
`rg "foo" -r "bar"`	Preview before using `sed` or an editor

Troubleshooting

Quick checks for common rg issues.

Issue	Check
File is missing from results	Run `rg --debug "pattern"`
Hidden files are skipped	Add `--hidden`
Ignored files are skipped	Add `--no-ignore`
Glob does not work	Quote it, for example `-g '*.conf'`
Pattern starts with `-`	Use `rg -e "--flag"`

Common Options

Useful flags to remember.

Option	Description
`-t TYPE`	Search only a file type
`-T TYPE`	Exclude a file type
`-g GLOB`	Include or exclude paths by glob
`-i`	Ignore case
`-S`	Smart case
`-F`	Fixed string search
`-w`	Whole-word match
`-l`	List matching files
`--files-without-match`	List non-matching files
`-C N`	Show context lines
`-r TEXT`	Preview replacement output
`--hidden`	Include hidden files
`--no-ignore`	Ignore ignore-file rules

Use these guides for full command workflows.

Guide	Description
ripgrep Command in Linux	Full `rg` tutorial with practical examples
grep Command in Linux	Standard text search with GNU `grep`
Grep Exclude	Exclude files, directories, and patterns with `grep`
find Files in Linux	Locate files by metadata and path
sed Find and Replace	Replace text after previewing matches

ss Cheatsheet

hello@linuxize.com (Linuxize) — Thu, 21 May 2026 10:00:00 +0200

Basic Syntax

Core ss command forms and output controls.

Command	Description
`ss`	Show non-listening sockets with an established connection
`ss -a`	Show all sockets, listening and non-listening
`ss -n`	Show numeric addresses and ports, no name resolution
`ss -p`	Show the process that owns each socket
`ss -s`	Show a summary of socket counts by type and state

Filter by Protocol

Restrict output to a single socket family.

Command	Description
`ss -t`	TCP sockets
`ss -u`	UDP sockets
`ss -x`	Unix domain sockets
`ss -ta`	All TCP sockets, including listening
`ss -4`	IPv4 sockets only
`ss -6`	IPv6 sockets only

Listening Ports

Find services that are accepting connections.

Command	Description
`ss -l`	Show listening sockets only
`ss -tl`	Listening TCP sockets
`ss -ul`	Listening UDP sockets
`ss -tulpn`	Listening TCP/UDP with process and numeric output
`sudo ss -tlpn 'sport = :80'`	Find the process listening on TCP port 80

Connection State Filters

Narrow output to a specific TCP state.

Command	Description
`ss -tn state ESTABLISHED`	Established TCP connections
`ss -tn state listening`	Listening TCP sockets
`ss -tn state TIME-WAIT`	Connections in `TIME-WAIT`
`ss -tn state CLOSE-WAIT`	Connections in `CLOSE-WAIT`
`ss -tn state ESTABLISHED \| tail -n +2 \| wc -l`	Count established TCP connections

Address and Port Filters

Match sockets by source or destination.

Command	Description
`ss -tnp 'dport = :443'`	Filter by destination port
`ss -tnp 'sport = :22'`	Filter by source port
`ss -tn dst 192.168.1.5`	Filter by remote address
`ss -tn src 192.168.1.10`	Filter by local address
`sudo ss -tlpn sport = :8080`	Find the process listening on port 8080

Process and Statistics

Tie sockets to processes and read summary counts.

Command	Description
`sudo ss -tp`	TCP sockets with process name and PID
`sudo ss -tulpn`	Listening sockets with owning processes
`ss -s`	Total sockets by transport and state
`ss -tn`	TCP sockets with numeric addresses
`ss -tn dst 203.0.113.10`	All connections to a remote host

netstat to ss Translation

Map old netstat commands to their ss equivalents.

netstat Command	ss Command
`netstat -tuln`	`ss -tuln`
`sudo netstat -tulnp`	`sudo ss -tulpn`
`netstat -at`	`ss -ta`
`netstat -ant \| grep ESTABLISHED`	`ss -tn state ESTABLISHED`
`netstat -s`	`ss -s`

Troubleshooting

Common ss issues and quick fixes.

Issue	Check
`-p` shows no process	Run with `sudo` to see sockets owned by other users
Filters return nothing	Quote the expression and verify `sport` versus `dport`
Service names hide ports	Add `-n` to keep numeric ports
Output too broad	Start with `-t`, `-u`, or a `state` filter, then narrow
Port match too broad	Use a built-in filter, such as `ss -tlpn 'sport = :80'`

Use these guides for full walkthroughs and related tools.

Guide	Description
`ss` Command in Linux	Full `ss` guide with examples
`netstat` Command in Linux	The legacy tool `ss` replaces
`ip` Command in Linux	Modern routes and interface management
How to Check Listening Ports in Linux	Compare `ss`, `netstat`, and `lsof`
`lsof` Command in Linux	Tie sockets and files back to processes

nmcli Cheatsheet

hello@linuxize.com (Linuxize) — Sun, 17 May 2026 10:40:00 +0200

Basic Syntax

Use this structure for most nmcli commands.

Command	Description
`nmcli [OPTIONS] OBJECT COMMAND`	General command syntax
`nmcli OBJECT help`	Show help for an object
`nmcli --version`	Show nmcli version
`nmcli -t ...`	Use terse output for scripts
`nmcli -f FIELD1,FIELD2 ...`	Select output fields
`nmcli -g FIELD ...`	Print field values only

General Status

Check NetworkManager state and hostname settings.

Command	Description
`nmcli general status`	Show overall NetworkManager status
`nmcli networking connectivity`	Check internet connectivity state
`nmcli general hostname`	Show system hostname
`sudo nmcli general hostname server01`	Set system hostname
`nmcli general permissions`	Show NetworkManager permissions
`nmcli general logging`	Show logging level and domains

Devices

Inspect and control network interfaces.

Command	Description
`nmcli device status`	List devices and connection state
`nmcli device show eth0`	Show detailed device properties
`nmcli -f GENERAL,IP4 device show eth0`	Show selected device sections
`sudo nmcli device connect eth0`	Connect a device
`sudo nmcli device disconnect eth0`	Disconnect a device
`nmcli device reapply eth0`	Reapply active profile settings

Connection Profiles

Manage saved NetworkManager profiles.

Command	Description
`nmcli connection show`	List all profiles
`nmcli connection show --active`	List active profiles
`nmcli connection show "home-wifi"`	Show one profile
`sudo nmcli connection up "home-wifi"`	Activate a profile
`sudo nmcli connection down "home-wifi"`	Deactivate a profile
`sudo nmcli connection delete "home-wifi"`	Delete a saved profile

Wi-Fi

Scan networks and connect to wireless profiles.

Command	Description
`nmcli radio wifi`	Show Wi-Fi radio state
`sudo nmcli radio wifi on`	Turn Wi-Fi on
`sudo nmcli radio wifi off`	Turn Wi-Fi off
`nmcli device wifi list`	Scan visible Wi-Fi networks
`sudo nmcli device wifi connect "SSID" password "PASSWORD"`	Connect with password
`sudo nmcli --ask device wifi connect "SSID"`	Prompt for Wi-Fi password
`sudo nmcli device wifi connect "SSID" password "PASSWORD" hidden yes`	Connect to hidden network

Static IPv4

Set or remove manual IPv4 settings on a profile.

Command	Description
`sudo nmcli connection modify "Wired connection 1" ipv4.method manual`	Use manual IPv4
`sudo nmcli connection modify "Wired connection 1" ipv4.addresses 192.168.1.50/24`	Set static address
`sudo nmcli connection modify "Wired connection 1" ipv4.gateway 192.168.1.1`	Set gateway
`sudo nmcli connection modify "Wired connection 1" ipv4.dns "1.1.1.1 9.9.9.9"`	Set DNS servers
`sudo nmcli connection up "Wired connection 1"`	Apply profile changes
`nmcli -g IP4.ADDRESS,IP4.GATEWAY connection show "Wired connection 1"`	Check IPv4 settings

DHCP and DNS

Return to DHCP or adjust DNS servers.

Command	Description
`sudo nmcli connection modify "Wired connection 1" ipv4.method auto`	Use DHCP for IPv4
`sudo nmcli connection modify "Wired connection 1" ipv4.addresses ""`	Clear static address
`sudo nmcli connection modify "Wired connection 1" ipv4.gateway ""`	Clear static gateway
`sudo nmcli connection modify "Wired connection 1" ipv4.dns ""`	Clear static DNS
`sudo nmcli connection modify "Wired connection 1" +ipv4.dns 8.8.8.8`	Append DNS server
`sudo nmcli connection modify "Wired connection 1" -ipv4.dns 8.8.8.8`	Remove DNS server

Add Profiles

Create new wired and wireless profiles.

Command	Description
`sudo nmcli connection add type ethernet ifname eth0 con-name "wired-dhcp"`	Add wired DHCP profile
`sudo nmcli connection add type ethernet ifname eth0 con-name "wired-static" ip4 192.168.1.50/24 gw4 192.168.1.1`	Add wired static profile
`sudo nmcli connection add type wifi ifname wlan0 con-name "office-wifi" ssid "Office"`	Add Wi-Fi profile
`sudo nmcli connection modify "office-wifi" wifi-sec.key-mgmt wpa-psk`	Set WPA-PSK security
`sudo nmcli connection modify "office-wifi" wifi-sec.psk "PASSWORD"`	Set Wi-Fi password
`sudo nmcli connection up "wired-static"`	Activate new profile

Scripting Output

Use stable output formats in scripts.

Command	Description
`nmcli -t connection show --active`	Terse active profile list
`nmcli -t -f NAME,DEVICE connection show --active`	Active names and devices
`nmcli -g GENERAL.STATE device show eth0`	Print device state value
`nmcli -g IP4.ADDRESS device show eth0`	Print IPv4 address values
`nmcli -f DEVICE,TYPE,STATE device status`	Select device status fields
`nmcli -m multiline connection show "home-wifi"`	Multiline profile details

Monitor and Reload

Watch changes and reload profile files.

Command	Description
`nmcli monitor`	Watch NetworkManager events
`nmcli device monitor eth0`	Watch one device
`sudo nmcli connection reload`	Reload profile files from disk
`sudo nmcli general reload`	Reload NetworkManager configuration
`sudo nmcli general reload dns-rc`	Rewrite DNS resolver configuration
`journalctl -u NetworkManager -n 100`	Show recent NetworkManager logs

Troubleshooting

Fast checks for common NetworkManager issues.

Issue	Check
NetworkManager is not running	`sudo systemctl start NetworkManager`
Wi-Fi list is empty	`sudo nmcli radio wifi on` and `rfkill list`
Wrong profile is active	`nmcli connection show --active`
Static IP did not apply	`sudo nmcli connection up "PROFILE"`
DNS is not working	`nmcli -g IP4.DNS device show eth0`
Permission denied	Run the command with `sudo`

Use these articles for detailed networking workflows.

Guide	Description
`nmcli Command in Linux`	Complete `nmcli` command guide
`Linux ip Command with Examples`	Interface, address, and route management
`How to Configure Static IP Address on Ubuntu`	Netplan and desktop static IP setup
`How to Use the dig Command`	DNS lookup and troubleshooting
`SSH Command in Linux`	Remote shell access and options

fdisk Cheatsheet

hello@linuxize.com (Linuxize) — Thu, 07 May 2026 12:10:00 +0200

Basic Usage

Open a disk or print partition tables.

Command	Description
`sudo fdisk /dev/sdX`	Open a disk in interactive mode
`sudo fdisk -l`	List all detected partition tables
`sudo fdisk -l /dev/sdX`	List one disk partition table
`sudo fdisk --help`	Show command-line options
`sudo fdisk --version`	Show fdisk version

List Disks

Identify the correct device before changing partitions.

Command	Description
`lsblk`	Show disks, partitions, and mount points
`lsblk -d -o NAME,SIZE,MODEL`	Show whole disks only
`lsblk -f`	Show filesystems and UUIDs
`sudo fdisk -l`	Show partition tables with disk labels
`sudo fdisk -x /dev/sdX`	Show detailed partition information

Interactive Commands

Commands used inside the fdisk prompt.

Command	Description
`m`	Show help menu
`p`	Print the current partition table
`n`	Create a new partition
`d`	Delete a partition
`t`	Change partition type
`l`	List available partition types
`w`	Write changes and exit
`q`	Quit without saving

Partition Tables

Create a new disk label before adding partitions on a blank disk.

Command	Description
`g`	Create a new GPT partition table
`o`	Create a new MBR (DOS) partition table
`p`	Review the current table before saving
`w`	Write the new table to disk
`q`	Exit without writing changes

Create Partitions

Common answers while creating a new partition with n.

Input	Description
`n`	Start a new partition
`Enter`	Accept the default partition number
`Enter`	Accept the default first sector
`+1G`	Create a 1 GiB partition
`+100G`	Create a 100 GiB partition
`Enter`	Use the rest of the available disk space
`p`	Print the proposed layout
`w`	Save the changes

Partition Types

Set the partition type when the partition is not a regular Linux data partition.

Input	Description
`l`	List partition types
`t`	Change a partition type
`Linux filesystem`	Regular Linux data partition (GPT)
`Linux swap`	Swap partition (GPT)
`EFI System`	EFI System partition (GPT)
`Linux LVM`	LVM physical volume (GPT)
`Linux RAID`	Linux RAID member (GPT)
`83`	Regular Linux partition (MBR)
`82`	Swap partition (MBR)
`8e`	LVM partition (MBR)

Review and Save

Check the in-memory table before writing it to disk.

Command	Description
`p`	Print the pending partition table
`v`	Verify the partition table
`i`	Show details about a partition
`w`	Write changes to disk and exit
`q`	Quit without saving changes

Format and Mount

After writing the partition table, create a filesystem and mount the partition.

Command	Description
`sudo mkfs.ext4 /dev/sdX1`	Format a partition as ext4
`sudo mkswap /dev/sdX2`	Create swap on a partition
`sudo swapon /dev/sdX2`	Enable swap
`sudo mkdir -p /mnt/data`	Create a mount point
`sudo mount /dev/sdX1 /mnt/data`	Mount the partition
`lsblk -f`	Confirm filesystem and mount details

Safety Checks

Commands that help avoid editing the wrong disk.

Command	Description
`lsblk -d -o NAME,SIZE,MODEL`	Compare disk names, sizes, and models
`lsblk -f`	Check existing filesystems and mount points
`sudo fdisk -l /dev/sdX`	Review the current table before editing
`mount \| grep /dev/sdX`	Check whether partitions are mounted
`sudo umount /dev/sdX1`	Unmount a partition before changing it
`sudo partprobe /dev/sdX`	Ask the kernel to re-read the table

References for the full workflow around disks and partitions.

Tool	Description
`mount`	Mount and unmount filesystems
`mkfs.ext4`	Format a partition with a filesystem
`df`	Check filesystem disk usage
`fsck`	Check and repair filesystems

SFTP Cheatsheet

hello@linuxize.com (Linuxize) — Thu, 07 May 2026 07:00:00 +0100

Connect and Authenticate

Open an SFTP session against a remote host.

Command	Description
`sftp user@hostname`	Connect to remote server
`sftp user@192.168.1.10`	Connect by IP
`sftp -P 2222 user@hostname`	Connect to a custom SSH port
`sftp -i ~/.ssh/id_ed25519 user@hostname`	Connect with a specific key
`sftp -b commands.txt user@hostname`	Run commands from a batch file
`quit`	Quit session
`bye`	Quit session (alias for `quit`)

Local and Remote Paths

Navigate directories on both sides of the session.

Command	Description
`pwd`	Show remote working directory
`lpwd`	Show local working directory
`cd /remote/path`	Change remote directory
`lcd /local/path`	Change local directory
`ls`	List remote files
`lls`	List local files
`ls -la`	Long listing of remote files

Download Files

Pull files from the remote server to the local system.

Command	Description
`get file.txt`	Download one file
`get remote.txt local.txt`	Download and rename locally
`get -r remote_dir`	Download a directory recursively
`get -P file.txt`	Preserve file permissions and timestamps
`mget *.log`	Download multiple files matching a pattern
`reget large.iso`	Resume an interrupted download

Upload Files

Push local files to the remote server.

Command	Description
`put file.txt`	Upload one file
`put local.txt remote.txt`	Upload with a remote name
`put -r local_dir`	Upload a directory recursively
`put -P file.txt`	Preserve permissions and timestamps
`mput *.txt`	Upload multiple files
`reput large.iso`	Resume an interrupted upload

Remote File Management

Manage files and directories on the SFTP server.

Command	Description
`mkdir dirname`	Create remote directory
`rmdir dirname`	Remove empty remote directory
`rm file.txt`	Delete remote file
`rename old.txt new.txt`	Rename remote file
`ln source link`	Create a hard link on the remote
`ln -s source link`	Create a symbolic link on the remote
`df -h`	Show remote filesystem usage

Permissions and Ownership

Adjust permissions and ownership on remote files.

Command	Description
`chmod 644 file.txt`	Change remote file mode
`chown 1000 file.txt`	Change remote owner by UID
`chgrp 1000 file.txt`	Change remote group by GID
`umask 022`	Set default permission mask

Session Helpers

Inspect and control the active session.

Command	Description
`!command`	Run a local shell command
`!`	Drop into a local shell
`version`	Show SFTP protocol version
`progress`	Toggle transfer progress meter
`help` or `?`	List available SFTP commands

Non-Interactive and Scripting

Use SFTP from scripts and automated jobs.

Command	Description
`sftp -b script.txt user@host`	Run a batch file of commands
`sftp -q user@host`	Quiet mode (suppress banner and progress)
`sftp -o IdentityFile=key user@host`	Pass any `ssh_config` option
`echo "get file.txt" \| sftp -b - user@host`	Pipe commands via stdin

Other ways to move files between systems.

Tool	Description
`scp`	Secure copy over SSH
`rsync`	Efficient sync and incremental transfer
`ssh`	Underlying secure shell protocol
`ftp`	Legacy unencrypted file transfer

cd Cheatsheet

hello@linuxize.com (Linuxize) — Sun, 03 May 2026 22:55:00 +0200

Basic Syntax

Core command forms for changing directories.

Command	Description
`cd [DIRECTORY]`	Change to a directory
`cd`	Change to your home directory
`cd -- DIRECTORY`	Change to a directory whose name may start with `-`
`pwd`	Print the current working directory

Common ways to move around the filesystem.

Command	Description
`cd /etc`	Change to an absolute path
`cd Downloads`	Change to a relative path
`cd ..`	Move up one directory
`cd ../..`	Move up two directories
`cd ./scripts`	Change to a directory under the current directory

Home Directories

Use shell shortcuts for your home directory and other users’ homes.

Command	Description
`cd ~`	Change to your home directory
`cd ~/Downloads`	Change to `Downloads` inside your home directory
`cd ~username`	Change to another user’s home directory
`cd "$HOME"`	Change to the directory stored in `$HOME`

Relative Paths

Build paths from your current directory.

Command	Description
`cd .`	Stay in the current directory
`cd ..`	Move to the parent directory
`cd ../src`	Move up one level, then into `src`
`cd ../../var`	Move up two levels, then into `var`
`cd project/docs`	Move through nested directories

Previous Directory

Switch between recently used directories.

Command	Description
`cd -`	Change to the previous working directory
`echo "$OLDPWD"`	Show the previous working directory
`cd "$OLDPWD"`	Change to the previous directory without using `cd -`
`pushd /path`	Change directory and save the old one on the stack
`popd`	Return to a directory from the stack

Paths with Spaces

Quote or escape paths that contain spaces or shell metacharacters.

Command	Description
`cd "Project Files"`	Quote a directory name with spaces
`cd 'Project Files'`	Use single quotes for a literal path
`cd Project\ Files`	Escape the space with a backslash
`cd -- "-reports"`	Enter a directory whose name starts with `-`

Symlinks and Physical Paths

Control whether cd follows logical or physical paths.

Command	Description
`cd -L linkdir`	Follow symbolic links (default in Bash)
`cd -P linkdir`	Resolve to the physical directory path
`pwd`	Show the shell’s logical current directory
`pwd -P`	Show the physical current directory
`cd -P ..`	Move using the physical directory structure

CDPATH

Search extra base directories when changing by name.

Command	Description
`export CDPATH=.:~/projects:/opt`	Search current directory, `~/projects`, and `/opt`
`cd myapp`	Try matching `myapp` in each `CDPATH` entry
`unset CDPATH`	Disable `CDPATH` for the current shell
`CDPATH= cd myapp`	Run one `cd` command without `CDPATH`

Troubleshooting

Quick checks for common directory-change errors.

Issue	Check
`No such file or directory`	Verify the path with `ls -ld path`
`Permission denied`	Check execute permission on the directory
Path with spaces fails	Quote the path or escape spaces
`cd -` fails	`$OLDPWD` is not set yet
Unexpected target with `CDPATH`	Run `unset CDPATH` or use an absolute path
Symlink path looks different	Compare `pwd` and `pwd -P`

Use these guides for detailed directory navigation workflows.

Guide	Description
`cd Command in Linux: Change Directories`	Full `cd` guide with examples
`How to Get the Current Working Directory in Linux`	Use `pwd` and understand the current directory
`pushd and popd Commands in Linux`	Work with the directory stack
`Linux Commands Cheatsheet`	General Linux command quick reference

netstat Cheatsheet

hello@linuxize.com (Linuxize) — Sat, 02 May 2026 10:30:00 +0100

Basic Syntax

Core netstat command forms and output controls.

Command	Description
`netstat`	Show active non-listening sockets
`sudo netstat -a`	Show all sockets
`sudo netstat -n`	Show numeric addresses and ports
`sudo netstat -p`	Show PID and program name where available
`sudo netstat -c`	Refresh output every second

Listening Ports

Find services that are accepting local connections.

Command	Description
`sudo netstat -tuln`	Show TCP and UDP listening sockets
`sudo netstat -tulnp`	Show listening sockets with PID and process name
`sudo netstat -tnlp`	Show listening TCP sockets only
`sudo netstat -unlp`	Show listening UDP sockets only
`sudo netstat -tulnp \| grep ':80'`	Find the process listening on port 80

Connections and TCP States

Inspect active connections and common TCP states.

Command	Description
`sudo netstat -at`	Show all TCP sockets
`sudo netstat -au`	Show all UDP sockets
`sudo netstat -ant`	Show TCP sockets with numeric addresses
`sudo netstat -ant \| grep ESTABLISHED`	Show established TCP connections
`sudo netstat -ant \| grep TIME_WAIT`	Show TCP connections in `TIME_WAIT`
`sudo netstat -atnc`	Watch TCP connection output continuously

Counts and Filters

Use shell filters with netstat output.

Command	Description
`sudo netstat -ant \| wc -l`	Count TCP output rows
`sudo netstat -ant \| grep ':80' \| wc -l`	Count TCP connections involving port 80
`sudo netstat -ant \| grep ESTABLISHED \| wc -l`	Count established TCP connections
`sudo netstat -tulnp \| grep nginx`	Find sockets owned by `nginx`
`sudo netstat -ant \| grep 203.0.113.10`	Filter connections by remote IP address

Routes, Interfaces, and Stats

Show routing, interface, and protocol information.

Command	Description
`netstat -rn`	Show the routing table with numeric addresses
`netstat -r`	Show the routing table with name resolution
`netstat -i`	Show interface counters
`netstat -ie`	Show extended interface details
`netstat -s`	Show protocol statistics
`netstat -st`	Show TCP protocol statistics
`netstat -su`	Show UDP protocol statistics

Modern Replacements

Use current Linux tools for new workflows and scripts.

netstat Command	Modern Command
`netstat -tuln`	`ss -tuln`
`sudo netstat -tulnp`	`sudo ss -tulnp`
`netstat -rn`	`ip route`
`netstat -i`	`ip -s link`
`netstat -s`	`ss -s`

Troubleshooting

Common netstat issues and quick fixes.

Issue	Check
`netstat: command not found`	Install the `net-tools` package or use `ss`
Process column is empty	Run with `sudo` when using `-p`
Output is slow	Add `-n` to disable name resolution
Port lookup matches too much	Search with a colon, such as `grep ':80'`
Need listeners only	Add `-l` with protocol flags such as `-tuln`

Use these guides for full walkthroughs and modern alternatives.

Guide	Description
`netstat` Command in Linux	Full `netstat` guide with examples
`ss` Command in Linux	Modern socket inspection tool
`ip` Command in Linux	Modern routes and interface management
How to Check Listening Ports in Linux	Compare `ss`, `netstat`, and `lsof`
`lsof` Command in Linux	Tie sockets and files back to processes

Netcat Cheatsheet

hello@linuxize.com (Linuxize) — Thu, 30 Apr 2026 11:20:00 +0100

Basic Syntax

Core nc command forms.

Command	Description
`nc host port`	Open a TCP connection
`nc -u host port`	Open a UDP connection
`nc -l port`	Listen on a local port
`nc -h`	Show help and options
`man nc`	Read the local Netcat manual

Connect and Listen

Create simple client and server connections.

Command	Description
`nc example.com 80`	Connect to TCP port 80
`nc -l 5555`	Listen on port 5555
`nc server.example.com 5555`	Connect to a listening host
`nc -v host 22`	Connect with verbose output
`nc -n 192.168.1.10 22`	Skip DNS lookups

Port Checks

Check whether TCP ports are open.

Command	Description
`nc -z -v host 22`	Check one TCP port
`nc -z -v host 20-80`	Check a port range
`nc -z -v host 80 443`	Check selected ports
`nc -z -w 3 host 443`	Check with a timeout
`nmap host`	Use Nmap for deeper scans

UDP

Use UDP instead of TCP.

Command	Description
`nc -u host 53`	Connect to a UDP service
`nc -u -l 5555`	Listen for UDP datagrams
`nc -z -v -u host 53`	Check a UDP port
`nc -u -w 3 host 123`	UDP check with timeout
`nc -u 192.168.1.10 5555`	Send text to a UDP listener

File Transfers

Send files between two hosts.

Command	Description
`nc -l 5555 > file`	Receive a file
`nc host 5555 < file`	Send a file
`nc -l 5555 \| tar xzvf -`	Receive and extract a directory
`tar czvf - dir \| nc host 5555`	Archive and send a directory
`nc -w 5 host 5555 < file`	Send with a timeout

HTTP and Raw Requests

Send plain text requests to network services.

Command	Description
`printf "GET / HTTP/1.1\r\nHost: example.com\r\n\r\n" \| nc example.com 80`	Send an HTTP request
`echo "QUIT" \| nc mail.example.com 25`	Send a simple SMTP command
`echo "PING" \| nc host 5555`	Send text to a listener
`nc host 80`	Type a request manually
`curl http://example.com`	Use curl for HTTP work

Timeouts and Persistent Listeners

Control how long Netcat waits and whether it keeps listening.

Command	Description
`nc -w 5 host 80`	Timeout after 5 seconds
`nc -k -l 5555`	Keep listening after disconnect
`nc -v -w 3 host 22`	Verbose connection with timeout
`nc -l 8080 < index.html`	Serve one file on port 8080
`while true; do nc -l 8080 < index.html; done`	Serve the file repeatedly

Troubleshooting

Quick checks for common Netcat issues.

Issue	Check
`nc: command not found`	Install `netcat-openbsd`, `netcat-traditional`, or `nmap-ncat`
Connection refused	Confirm the remote service is running and listening on that port
Command hangs	Add `-w` to set a timeout
UDP result is unclear	UDP has no TCP-style handshake, use Nmap for reliable scans
Option behaves differently	Run `man nc` and check the Netcat implementation on that system

Use these guides for broader networking workflows.

Guide	Description
Netcat Command in Linux	Full Netcat guide with examples
Nmap Command in Linux	Scan hosts and ports in more detail
curl cheatsheet	Work with HTTP requests and APIs
tcpdump cheatsheet	Capture and inspect network packets
ss Command in Linux	Inspect sockets and listening services

timedatectl Cheatsheet

hello@linuxize.com (Linuxize) — Tue, 21 Apr 2026 09:20:00 +0100

Basic Status

Check the current time, date, time zone, and sync state.

Command	Description
`timedatectl`	Show current time, time zone, and NTP status
`timedatectl status`	Show the same formatted status explicitly
`timedatectl show`	Show status in key-value format
`timedatectl show --property=Timezone --value`	Print the current time zone only
`timedatectl show --property=NTPSynchronized --value`	Print whether the clock is synchronized

Time Zones

List and change time zone settings.

Command	Description
`timedatectl list-timezones`	List all available time zones
`timedatectl list-timezones \| grep -i berlin`	Filter the time zone list
`sudo timedatectl set-timezone Europe/Berlin`	Set the system time zone
`sudo timedatectl set-timezone Etc/UTC`	Switch the system back to UTC
`timedatectl show --property=Timezone --value`	Confirm the current time zone in scripts

NTP Synchronization

Enable, disable, and inspect time synchronization.

Command	Description
`sudo timedatectl set-ntp true`	Enable automatic time sync
`sudo timedatectl set-ntp false`	Disable automatic time sync
`timedatectl timesync-status`	Show the current NTP server, offset, and poll interval
`timedatectl show-timesync`	Show timesync details in key-value format
`timedatectl show --property=NTP --value`	Show whether NTP is enabled

Set Time and Date

Disable NTP first when setting the clock manually.

Command	Description
`sudo timedatectl set-ntp false`	Turn off NTP before manual changes
`sudo timedatectl set-time '2026-04-21 14:30:00'`	Set both date and time
`sudo timedatectl set-time '14:30:00'`	Set the time only
`sudo timedatectl set-time '2026-04-21'`	Set the date only
`sudo timedatectl set-ntp true`	Re-enable NTP after manual changes

RTC and Hardware Clock

Control whether the RTC uses UTC or local time.

Command	Description
`timedatectl show --property=LocalRTC --value`	Check whether the RTC uses local time
`sudo timedatectl set-local-rtc 0`	Set the RTC to UTC
`sudo timedatectl set-local-rtc 1`	Set the RTC to local time
`sudo timedatectl set-local-rtc 1 --adjust-system-clock`	Switch RTC mode and adjust the system clock
`timedatectl`	Confirm the `RTC in local TZ` status line

Script-Friendly Output

Extract single values for shell scripts and automation.

Command	Description
`timedatectl show --property=Timezone --value`	Get the current time zone
`timedatectl show --property=LocalRTC --value`	Get the RTC mode
`timedatectl show --property=CanNTP --value`	Check whether NTP is supported
`timedatectl show --property=NTP --value`	Check whether NTP is enabled
`timedatectl show --property=NTPSynchronized --value`	Check whether the clock is synchronized

Remote and Container Use

Run timedatectl against another host or a local container.

Command	Description
`timedatectl -H user@server status`	Check time settings on a remote host over SSH
`timedatectl -H root@server set-timezone UTC`	Change the remote host time zone
`timedatectl -M mycontainer status`	Check time settings in a local container
`timedatectl -M mycontainer show --property=Timezone --value`	Print the container time zone only

Quick Fixes

Use these when timedatectl does not behave as expected.

Command	Description
`sudo timedatectl set-ntp false`	Fix `Automatic time synchronization is enabled` before `set-time`
`timedatectl timesync-status`	Check which server is syncing the clock
`timedatectl --no-pager`	Print directly without opening a pager
`sudo date -s '2026-04-21 14:30:00'`	Set the clock on non-systemd systems where `timedatectl` does not work

Use these articles for deeper explanations and step-by-step instructions.

Guide	Description
`How to Set or Change the Time Zone in Linux`	Change the system time zone with `timedatectl`, `tzdata`, or `/etc/localtime`
`date Command in Linux`	Read and set the system clock with the traditional `date` command
`journalctl Cheatsheet`	Inspect time sync and service logs from the systemd journal

PostgreSQL Cheatsheet

hello@linuxize.com (Linuxize) — Thu, 16 Apr 2026 15:50:00 +0200

Basic Syntax

Core PostgreSQL command forms.

Command	Description
`psql`	Open an interactive PostgreSQL shell using local defaults
`psql -U user -d dbname`	Connect as a specific user to a specific database
`psql -h host -p 5432 -U user -d dbname`	Connect to a remote PostgreSQL server
`psql -c "SQL_STATEMENT"`	Run one SQL command and exit
`sudo -u postgres psql`	Open `psql` as the local `postgres` superuser

Connect and Switch

Common ways to connect and move between databases.

Command	Description
`sudo -u postgres psql`	Connect locally as the `postgres` system user
`psql -U app_user -d app_db`	Connect to `app_db` as `app_user`
`psql "host=localhost port=5432 dbname=app_db user=app_user"`	Connect with a connection string
`\c app_db`	Switch to another database inside `psql`
`\conninfo`	Show the current connection details

Databases

Create, list, rename, and remove databases.

Command	Description
`CREATE DATABASE app_db;`	Create a new database
`CREATE DATABASE app_db OWNER app_user;`	Create a database owned by a specific role
`\l`	List databases
`ALTER DATABASE app_db RENAME TO app_prod;`	Rename a database
`DROP DATABASE app_db;`	Delete a database

Roles and Users

Create login roles and inspect existing roles.

Command	Description
`CREATE ROLE app_user;`	Create a role without login
`CREATE ROLE app_user WITH LOGIN PASSWORD 'strong_password';`	Create a login role
`CREATE USER app_user WITH PASSWORD 'strong_password';`	Shortcut for a login role
`ALTER ROLE app_user WITH PASSWORD 'new_password';`	Change a role password
`\du`	List roles and attributes

Grant and Revoke Privileges

Give or remove access at the database, schema, and table levels.

Command	Description
`GRANT CONNECT ON DATABASE app_db TO app_user;`	Allow a role to connect to a database
`GRANT USAGE, CREATE ON SCHEMA public TO app_user;`	Allow schema access and object creation
`GRANT SELECT, INSERT, UPDATE, DELETE ON TABLE orders TO app_user;`	Grant table privileges
`REVOKE INSERT, UPDATE ON TABLE orders FROM app_user;`	Remove selected table privileges
`ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT SELECT ON TABLES TO app_user;`	Grant defaults for future tables

Table and Schema Introspection

Inspect schemas, tables, columns, and query results.

Command	Description
`\dn`	List schemas
`\dt`	List tables in the current search path
`\dt public.*`	List tables in the `public` schema
`\d orders`	Describe a table, view, or sequence
`SELECT * FROM orders LIMIT 10;`	Preview rows from a table

psql Meta-Commands

Useful built-in psql commands for daily administration.

Command	Description
`\?`	Show `psql` meta-command help
`\h CREATE ROLE`	Show SQL help for one statement
`\x`	Toggle expanded output for wide rows
`\timing`	Toggle query timing display
`\q`	Quit `psql`

Backup and Restore

Common logical backup and restore commands.

Command	Description
`pg_dump -U app_user -d app_db > app_db.sql`	Export a database as plain SQL
`pg_dump -Fc -U app_user -d app_db -f app_db.dump`	Create a custom-format backup
`psql -U app_user -d app_db < app_db.sql`	Restore a plain SQL dump
`pg_restore -U app_user -d app_db app_db.dump`	Restore a custom-format dump
`pg_dumpall > cluster.sql`	Back up all databases and global objects

Version and Service Checks

Quick checks for server version and service status.

Command	Description
`SELECT version();`	Show the PostgreSQL server version
`psql --version`	Show the client version
`SHOW server_version;`	Show the server version only
`sudo systemctl status postgresql`	Check the PostgreSQL service state
`sudo systemctl restart postgresql`	Restart the PostgreSQL service

Use these guides for full PostgreSQL walkthroughs.

Guide	Description
PostgreSQL User Management: Create Users and Grant Privileges	Full guide to roles, passwords, and grants
How to Check the PostgreSQL Version	Find the installed and running PostgreSQL version
How to Install PostgreSQL on Ubuntu 20.04	Install PostgreSQL on Ubuntu
How to Install PostgreSQL on Debian 10	Install PostgreSQL on Debian
How to Install PostgreSQL on CentOS 8	Install PostgreSQL on CentOS

du Cheatsheet

hello@linuxize.com (Linuxize) — Mon, 13 Apr 2026 14:49:31 +0200

Basic Usage

Common ways to check directory and file sizes.

Command	Description
`du`	Show disk usage of the current directory and its subdirectories
`du file`	Show disk usage of a single file
`du dir1 dir2`	Show disk usage for multiple paths
`du -h dir`	Human-readable sizes (K, M, G)
`du -sh dir`	Show only the total size of a directory
`du -sh *`	Show the size of every item in the current directory
`sudo du -sh /var`	Run with sudo to read root-owned paths

Size Formats

Control how sizes are printed.

Option	Description
`-h`	Human-readable, powers of 1024 (`K`, `M`, `G`)
`-H`	Human-readable, powers of 1000 (SI units)
`-k`	Display sizes in 1K blocks (default on most systems)
`-m`	Display sizes in 1M blocks
`-BG`	Display sizes in 1G blocks
`-B SIZE`	Use SIZE-byte blocks, for example `-BM` or `-B512`
`-b`	Equivalent to `--apparent-size --block-size=1`

Summary and Totals

Reduce noise or add a grand total row.

Command	Description
`du -s dir`	Show only the total for the given directory
`du -sh dir`	Total in human-readable format
`du -c dir1 dir2`	Add a `total` line at the bottom
`du -csh /var/log /var/lib`	Human-readable totals plus a combined grand total
`du -a dir`	Include every file in the listing, not just directories

Depth Control

Limit how deep du descends into the directory tree.

Command	Description
`du -h --max-depth=1 dir`	Show only the first level of subdirectories
`du -h --max-depth=2 dir`	Show two levels deep
`du -h -d 1 dir`	Short form of `--max-depth=1`
`du -h --max-depth=0 dir`	Show only the directory total (same as `-s`)

Excluding Files

Skip paths or patterns from the report.

Option	Description
`--exclude=PATTERN`	Skip files and directories matching the shell pattern
`--exclude-from=FILE`	Read exclude patterns from a file
`-x`	Stay on the same filesystem (skip mounted ones)

Examples:

Command	Description
`du -sh --exclude="*.log" /var`	Exclude `.log` files from the total
`du -sh --exclude=node_modules ~/projects`	Skip `node_modules` directories
`du -xsh /`	Total of the root filesystem only, ignoring mounts

Sorting and Top N

Combine du with sort and head to find the largest items.

Command	Description
`du -h dir \| sort -rh`	Sort entries by size, largest first
`du -h dir \| sort -rh \| head -10`	List the 10 largest items
`du -h --max-depth=1 / \| sort -rh \| head -20`	Largest top-level directories under `/`
`du -ah dir \| sort -rh \| head -10`	Largest individual files and directories
`du -sh */ \| sort -rh`	Sort current directory’s children by size

Apparent vs Disk Usage

du reports allocated blocks by default. Use these flags to see actual byte counts.

Option	Description
`--apparent-size`	Show how many bytes the file contains, not how much it occupies on disk
`-b`	Apparent size in bytes (shorthand for `--apparent-size --block-size=1`)

Examples:

Command	Description
`du -sh --apparent-size /var/log`	Apparent size of `/var/log`
`du -sb file`	Exact byte count of a file

Counting and Time

Less common but useful options.

Option	Description
`-L`	Follow all symbolic links
`-P`	Never follow symbolic links (default)
`-l`	Count sizes many times if hard linked
`--time`	Show last modification time of the file or directory
`--time=atime`	Show the access time instead of modification time
`-0`	Use a NUL character as the line separator (for piping into `xargs -0`)

Use these references for deeper disk usage workflows.

Guide	Description
`du Command in Linux`	Full `du` guide with practical examples
`How to Get the Size of a File or Directory`	Focused walkthrough for sizing files and directories
`How to Check Disk Space in Linux Using df`	Filesystem-level disk space reporting
`Find Large Files in Linux`	Locate the biggest files across a tree

nslookup Cheatsheet

hello@linuxize.com (Linuxize) — Sat, 11 Apr 2026 14:20:00 +0200

Basic Syntax

Core nslookup command forms.

Command	Description
`nslookup example.com`	Look up a domain using the default resolver
`nslookup example.com 8.8.8.8`	Query a specific DNS server
`nslookup -type=mx example.com`	Query a specific record type
`nslookup 192.0.2.1`	Run a reverse DNS lookup
`nslookup`	Start interactive mode

Common Lookups

Quick checks for hostnames and addresses.

Command	Description
`nslookup example.com`	Look up A and AAAA records using the default resolver
`nslookup www.example.com`	Check a hostname or subdomain
`nslookup localhost`	Verify local name resolution
`nslookup 127.0.0.1`	Reverse lookup for the local loopback address
`nslookup 192.0.2.1`	Reverse lookup for a public IP address

Record Types

Use -type to query specific DNS records.

Command	Description
`nslookup -type=a example.com`	Query IPv4 address records
`nslookup -type=aaaa example.com`	Query IPv6 address records
`nslookup -type=mx example.com`	Query mail exchanger records
`nslookup -type=ns example.com`	Query authoritative name servers
`nslookup -type=txt example.com`	Query TXT records
`nslookup -type=soa example.com`	Query the SOA record
`nslookup -type=cname www.example.com`	Check whether a hostname is an alias
`nslookup -type=any example.com`	Run an `ANY` query

Specific DNS Servers

Compare answers from different resolvers.

Command	Description
`nslookup example.com 8.8.8.8`	Query Google Public DNS
`nslookup example.com 1.1.1.1`	Query Cloudflare DNS
`nslookup example.com 9.9.9.9`	Query Quad9
`nslookup -type=mx example.com 8.8.8.8`	Query MX records from a specific resolver
`nslookup -type=txt example.com 1.1.1.1`	Compare TXT answers between resolvers

Interactive Mode

Run multiple queries in one session.

Command	Description
`nslookup`	Open interactive mode
`set type=mx`	Switch the active query type to MX
`set type=txt`	Switch the active query type to TXT
`server 8.8.8.8`	Change the active DNS server
`example.com`	Query a domain after entering interactive mode
`exit`	Leave the interactive session

Troubleshooting

Quick checks for common nslookup errors.

Issue	Check
`NXDOMAIN`	Verify the domain name and make sure it exists
`SERVFAIL`	Try another resolver such as `8.8.8.8` or `1.1.1.1`
`Connection timed out; no servers could be reached`	Check network access and verify `/etc/resolv.conf`
`Non-authoritative answer`	Normal cached response from a resolver
`No answer`	The queried record type is not set for that name

Use these guides for fuller DNS troubleshooting workflows.

Guide	Description
nslookup Command in Linux	Full `nslookup` guide with practical examples
How to Use the dig Command to Query DNS in Linux	Detailed `dig` guide for deeper DNS debugging
ping Cheatsheet	Quick connectivity checks before DNS troubleshooting
IP command cheatsheet	Inspect interfaces, addresses, and routes
curl Cheatsheet	Test HTTP reachability after DNS resolution succeeds

tail Cheatsheet

hello@linuxize.com (Linuxize) — Tue, 07 Apr 2026 11:40:00 +0200

Basic Syntax

Core tail command forms.

Command	Description
`tail FILE`	Show the last 10 lines of a file
`tail -n 20 FILE`	Show the last 20 lines
`tail -f FILE`	Follow a file as new lines are appended
`tail -c 200 FILE`	Show the last 200 bytes
`command \| tail`	Show the end of piped output

Show the Last Lines

Common line-based usage patterns.

Command	Description
`tail /var/log/syslog`	Show the last 10 lines of a system log
`tail -n 50 /var/log/nginx/access.log`	Show the last 50 log lines
`tail -5 file.txt`	Short form for the last 5 lines
`tail -n 1 file.txt`	Show only the last line
`tail -n +5 file.txt`	Start printing from line 5

Follow Logs in Real Time

Monitor changing files without reopening them.

Command	Description
`tail -f /var/log/auth.log`	Follow a log file live
`tail -n 100 -f app.log`	Show recent lines, then keep following
`tail -F /var/log/nginx/error.log`	Follow by filename and survive log rotation
`sudo tail -f /var/log/secure`	Follow a root-owned log file
`tail -f --pid=1234 app.log`	Stop following when PID 1234 exits

Bytes and Starting Positions

Switch from lines to byte counts or start offsets.

Command	Description
`tail -c 500 file.bin`	Show the last 500 bytes
`tail -c 2K file.log`	Show the last 2 KiB
`tail -n +2 file.csv`	Skip the first line, useful for headers
`tail -n +20 file.txt`	Print from line 20 to the end
`tail -c +101 file.txt`	Print starting from byte 101

Multiple Files

Inspect or follow more than one file at a time.

Command	Description
`tail file1.log file2.log`	Show the last 10 lines from each file
`tail -n 20 file1.log file2.log`	Show the last 20 lines from each file
`tail -f /var/log/syslog /var/log/auth.log`	Follow multiple log files live
`tail -q file1 file2`	Suppress file headers
`tail -v file1 file2`	Always show file headers

Pipelines and Combos

Use tail with other text-processing tools.

Command	Description
`dmesg \| tail -n 20`	Show the most recent kernel messages
`ps aux \| sort -nk 3 \| tail -5`	Show processes with the highest CPU usage
`grep ERROR app.log \| tail -n 20`	Show the latest matching error lines
`tail -n +20 file.txt \| head -n 11`	Extract lines 20 through 30
`journalctl -u nginx \| tail -n 50`	Show the latest service log lines

Troubleshooting

Quick checks for common tail confusion.

Issue	Check
No new output appears with `-f`	Confirm the file is still being written to and you are watching the correct path
Output stops after log rotation	Use `tail -F` to follow the filename instead of the old file descriptor
`Permission denied`	Check file ownership and run with the correct user or `sudo` if needed
Need only one field or last value	Combine `tail` with `awk` or `cut` after confirming the file format
Wrong starting line with `+N`	Remember `tail -n +N` starts printing at line `N`, not after it

Use these guides for full logging and text-processing workflows.

Guide	Description
tail Command in Linux	Full `tail` guide with examples
head Command in Linux	Show the first lines of files
less Command in Linux	Scroll, search, and follow file output
grep Command in Linux	Filter matching log lines
linux wc Command	Count lines and bytes in files

htop Cheatsheet

hello@linuxize.com (Linuxize) — Mon, 06 Apr 2026 11:35:00 +0200

Basic Usage

Start htop and limit the view when needed.

Command	Description
`htop`	Start `htop` with the default interactive view
`htop -u username`	Show only processes owned by one user
`htop -p 1234,5678`	Monitor only the specified PIDs
`htop -t`	Start in tree view
`sudo htop`	Run with elevated privileges to manage more processes

Move around the process list and find what you need quickly.

Key	Description
`Arrow keys`	Move up and down through processes
`Page Up` / `Page Down`	Scroll one page at a time
`Home` / `End`	Jump to the top or bottom of the list
`F3` or `/`	Search for a process by name
`F4` or `\\`	Filter the process list
`Space`	Tag or untag the selected process
`U`	Clear all tags

Sorting and Views

Change how processes are grouped and sorted.

Key / Command	Description
`P`	Sort by CPU usage
`M`	Sort by memory usage
`T`	Sort by running time
`F5`	Toggle tree view
`F6`	Choose a sort column
`htop -s PERCENT_MEM`	Start sorted by memory usage
`H`	Toggle display of user threads
`K`	Toggle display of kernel threads

Process Actions

Manage processes directly from inside htop.

Key	Description
`F7`	Decrease nice value (raise priority)
`F8`	Increase nice value (lower priority)
`F9`	Send a signal to the selected process
`15 SIGTERM`	Ask a process to exit cleanly
`9 SIGKILL`	Force a process to stop immediately
`2 SIGINT`	Interrupt a process, similar to `Ctrl+C`
`q` or `F10`	Quit `htop`

Startup Options

Useful options for changing the initial view.

Command	Description
`htop -d 20`	Refresh every 2 seconds
`htop -C`	Use monochrome mode
`htop -H`	Highlight new and old processes
`htop --readonly`	Disable process-kill and renice actions
`htop --sort-key PERCENT_CPU`	Start sorted by CPU usage

Customization

Adjust the display and save the layout.

Key / Path	Description
`F2`	Open the setup menu
`Columns`	Add, remove, or reorder process columns
`Meters`	Change header meters and display style
`Display options`	Toggle tree lines, thread names, and other UI settings
`~/.config/htop/htoprc`	Configuration file where settings are saved

Troubleshooting

Quick checks for common htop issues.

Issue	Check
`htop: command not found`	Install `htop` with `apt` or `dnf` first
Cannot renice a process	Run `htop` with `sudo` to change priorities for other users’ processes
Cannot kill a process	Confirm you have permission, then use `F9` with `SIGTERM` first
Process list is too noisy	Use `F4` to filter or start with `-u USER`
Fast processes disappear	Lower the update interval with `-d`

Use these guides for the full walkthroughs.

Guide	Description
`htop` Command in Linux	Full `htop` guide with examples
`top` Command in Linux	Monitor processes in real time with `top`
`ps` Command in Linux	List and inspect processes
`kill` Command in Linux	Send signals to processes by PID
`pstree` Command in Linux	View parent and child process relationships

lsof Cheatsheet

hello@linuxize.com (Linuxize) — Wed, 01 Apr 2026 11:20:00 +0100

Basic Syntax

Core lsof command forms.

Command	Description
`lsof`	List open files visible to the current user
`sudo lsof`	List open files system-wide
`lsof /path/to/file`	Show which process has a file open
`lsof -p 1234`	Show files opened by one PID
`lsof -u username`	Show files opened by one user

Port and Network Checks

Find listeners and active network connections.

Command	Description
`sudo lsof -nP -iTCP:80 -sTCP:LISTEN`	Find what is listening on TCP port 80
`sudo lsof -i`	List all network connections
`sudo lsof -i TCP`	List TCP connections
`sudo lsof -i UDP`	List UDP connections
`sudo lsof -nP -iTCP:443 -sTCP:LISTEN`	Filter to listeners on TCP port 443

Process and User Filters

Filter open files by process, command name, or user.

Command	Description
`sudo lsof -p 1234`	Files opened by PID 1234
`sudo lsof -p ^1234`	Exclude PID 1234
`sudo lsof -c nginx`	Files opened by commands starting with `nginx`
`lsof -u john`	Files opened by user `john`
`sudo lsof -u ^john`	Exclude files opened by user `john`

Files and Directories

Check who is using a file or directory tree.

Command	Description
`lsof /var/log/nginx/access.log`	Show processes using one file
`sudo lsof +d /var/log`	Show open files in one directory level
`sudo lsof +D /var/log`	Show open files in a directory recursively
`sudo lsof +D /mountpoint`	Find what is blocking an unmount
`sudo lsof /dev/sda`	Check processes using a device file

Deleted Files and Disk Space

Find deleted files that still consume disk space.

Command	Description
`sudo lsof +L1`	List deleted files still held open
`sudo lsof +L1 /var`	Limit deleted-file search to one path
`sudo lsof -a +L1 -u nginx`	Deleted files still open for one user
`sudo lsof +L1 \| sort -k7 -n`	Sort deleted-file output by size/off column
`sudo lsof +L1 \| grep deleted`	Quick filter for deleted entries

Scripting and Combined Filters

Use lsof in scripts and tighter searches.

Command	Description
`sudo lsof -t -iTCP:8080 -sTCP:LISTEN`	Output only the PID listening on port 8080
`sudo lsof -a -u john -i TCP`	Show only TCP connections owned by `john`
`sudo lsof -a -p 1234 -d cwd`	Show only the current working directory for one PID
`sudo lsof -Fn -p 1234`	Machine-readable output for scripts
`kill $(sudo lsof -t -iTCP:8080 -sTCP:LISTEN)`	Stop the process listening on port 8080

Troubleshooting

Quick checks for common lsof usage issues.

Issue	Check
Output looks incomplete	Run with `sudo` to see files opened by other users’ processes
Port lookup shows service names instead of numbers	Add `-nP` for numeric addresses and ports
Need listeners only, not all connections	Add `-sTCP:LISTEN` with `-iTCP:PORT`
Recursive directory search is slow	Prefer `+d` for top-level only, or narrow the path
Disk space is still not freed after delete	Use `lsof +L1` and restart the process holding the file

Use these guides for the full walkthroughs.

Guide	Description
`lsof` Command in Linux	Full `lsof` guide with examples
`ss` Command in Linux	Inspect sockets and listening services
How to Check Listening Ports in Linux	Compare `ss`, `netstat`, and `lsof`
Find Large Files in Linux	Track disk usage and deleted files
`ps` Command in Linux	Inspect processes and related details

fsck Cheatsheet

hello@linuxize.com (Linuxize) — Sat, 28 Mar 2026 11:00:00 +0100

Basic Usage

Common fsck command forms.

Command	Description
`fsck /dev/sdb1`	Check a filesystem
`fsck -n /dev/sdb1`	Check only, do not write changes
`fsck -f /dev/sdb1`	Force a check even if the filesystem looks clean
`fsck -t ext4 /dev/sdb1`	Check only filesystems of the given type
`fsck -A`	Check filesystems listed in `/etc/fstab`

Safe Repair Workflow

Use this sequence before making repairs.

Command	Description
`lsblk -f`	Identify the device, mount point, and filesystem type
`mount \| grep /dev/sdb1`	Confirm whether the device is mounted
`sudo umount /dev/sdb1`	Unmount the filesystem before repair
`sudo fsck -n /dev/sdb1`	Run a read-only check first
`sudo fsck -p /dev/sdb1`	Auto-fix safe problems without prompts

Repair Modes

Choose how interactive the repair should be.

Option	Description
`-n`	Do not make changes, useful for a safe first pass
`-p`	Automatically repair safe problems
`-y`	Answer yes to all prompts
`-r`	Prompt before each repair
`-f`	Force checking even if the filesystem appears clean

Filesystem Selection

Target one filesystem, one type, or all entries in fstab.

Command	Description
`sudo fsck /dev/nvme0n1p2`	Check one device directly
`sudo fsck -t ext4 /dev/nvme0n1p2`	Check one device as `ext4`
`sudo fsck -A`	Check all eligible filesystems in `/etc/fstab`
`sudo fsck -AR`	Check all except the root filesystem
`sudo fsck.ext4 /dev/nvme0n1p2`	Run the filesystem-specific checker directly

Root Filesystem Recovery

fsck cannot repair the mounted root filesystem on a running system.

Method	Description
Recovery mode	Boot into recovery and choose the filesystem check option
Live USB	Boot a live system, identify the root partition, then run `fsck` there
`fsck.mode=force`	Kernel parameter to force a check during boot on systemd systems
`fsck.repair=yes`	Kernel parameter to approve repairs during boot
`sudo touch /forcefsck`	Older non-systemd pattern to force a boot-time check

tune2fs Scheduling

Control when ext filesystems are checked automatically.

Command	Description
`sudo tune2fs -l /dev/sdb1 \| grep -i 'last checked\|mount count'`	Show last check time and mount counters
`sudo tune2fs -c 25 /dev/sdb1`	Run a check after every 25 mounts
`sudo tune2fs -c -1 /dev/sdb1`	Disable mount-count-based checks
`sudo tune2fs -i 1m /dev/sdb1`	Run a check at most once per month
`sudo tune2fs -i 0 /dev/sdb1`	Disable time-based checks

fstab Pass Values

The sixth /etc/fstab column controls boot-time check order.

Value	Description
`0`	Do not check this filesystem at boot
`1`	Check first, usually the root filesystem
`2`	Check after root, for other local filesystems

Example: /dev/sda2 /home ext4 defaults 0 2

Exit Codes

Use exit codes to understand what fsck found.

Code	Description
`0`	No errors
`1`	Filesystem errors corrected
`2`	System should be rebooted
`4`	Filesystem errors left uncorrected
`8`	Operational error
`16`	Usage or syntax error
`32`	Checking canceled by user
`128`	Shared-library error

Other Filesystems

Some filesystems use tools other than fsck.

Filesystem	Tool
XFS	`xfs_repair`
Btrfs	`btrfs check` or `btrfs scrub`
NTFS	`ntfsfix`
FAT/VFAT	`fsck.vfat`
Ext2/3/4	`fsck.ext2`, `fsck.ext3`, `fsck.ext4`

Use these articles for the full workflow around filesystem repair.

Guide	Description
`Fsck Command in Linux (Repair Filesystem)`	Full `fsck` guide with examples
`How to Check Disk Space in Linux Using the df Command`	Check mounted filesystems and free space
`How to Mount and Unmount File Systems in Linux`	Unmount a filesystem before repair
`Sudo Command in Linux: Run Commands as Root`	Run `fsck` with the required privileges

firewalld Cheatsheet

hello@linuxize.com (Linuxize) — Wed, 25 Mar 2026 11:00:00 +0100

Basic Commands

Start, stop, and reload the firewalld service.

Command	Description
`firewall-cmd --state`	Check if firewalld is running
`sudo systemctl start firewalld`	Start the service
`sudo systemctl stop firewalld`	Stop the service
`sudo systemctl enable firewalld`	Enable at boot
`sudo systemctl disable firewalld`	Disable at boot
`sudo firewall-cmd --reload`	Reload rules without dropping connections
`sudo firewall-cmd --complete-reload`	Full reload, resets all connections

Runtime vs Permanent

By default, firewall-cmd changes apply at runtime only and are lost on reload. Add --permanent to persist a rule, then reload to activate it.

Command	Description
`sudo firewall-cmd --add-service=http`	Allow HTTP (runtime only)
`sudo firewall-cmd --add-service=http --permanent`	Allow HTTP (survives reload)
`sudo firewall-cmd --reload`	Activate permanent rules
`sudo firewall-cmd --runtime-to-permanent`	Save all runtime rules as permanent

Zones

Zones define trust levels for network connections. Each interface belongs to one zone.

Command	Description
`firewall-cmd --get-zones`	List all available zones
`firewall-cmd --get-default-zone`	Show the default zone
`sudo firewall-cmd --set-default-zone=public`	Set the default zone
`firewall-cmd --get-active-zones`	Show active zones and their interfaces
`firewall-cmd --zone=public --list-all`	List all settings for a zone
`sudo firewall-cmd --zone=public --change-interface=eth0`	Assign interface to zone (runtime)
`sudo firewall-cmd --zone=public --add-interface=eth0 --permanent`	Assign interface permanently
`sudo firewall-cmd --zone=public --remove-interface=eth0`	Remove interface from zone

Services

Allow or block named services defined in /usr/lib/firewalld/services/.

Command	Description
`firewall-cmd --get-services`	List all predefined services
`firewall-cmd --zone=public --list-services`	List services allowed in zone
`firewall-cmd --info-service=http`	Show ports and protocols for a service
`sudo firewall-cmd --zone=public --add-service=http --permanent`	Allow service permanently
`sudo firewall-cmd --zone=public --remove-service=http --permanent`	Remove service

Ports

Open or close individual ports when no predefined service exists.

Command	Description
`firewall-cmd --zone=public --list-ports`	List open ports in zone
`sudo firewall-cmd --zone=public --add-port=8080/tcp --permanent`	Open a TCP port
`sudo firewall-cmd --zone=public --add-port=4000-4500/tcp --permanent`	Open a port range
`sudo firewall-cmd --zone=public --remove-port=8080/tcp --permanent`	Close a port

Rich Rules

Rich rules allow fine-grained control over source, destination, port, and action.

Command	Description
`firewall-cmd --zone=public --list-rich-rules`	List rich rules in zone
`sudo firewall-cmd --zone=public --add-rich-rule='rule family="ipv4" source address="192.168.1.0/24" accept' --permanent`	Allow traffic from subnet
`sudo firewall-cmd --zone=public --add-rich-rule='rule family="ipv4" source address="203.0.113.10" reject' --permanent`	Reject traffic from IP
`sudo firewall-cmd --zone=public --add-rich-rule='rule family="ipv4" source address="192.168.1.0/24" port port="22" protocol="tcp" accept' --permanent`	Allow SSH from subnet
`sudo firewall-cmd --zone=public --remove-rich-rule='rule family="ipv4" source address="203.0.113.10" reject' --permanent`	Remove a rich rule

Masquerade (NAT)

Masquerading lets machines on a private network reach the internet through the firewall host.

Command	Description
`firewall-cmd --zone=public --query-masquerade`	Check if masquerading is enabled
`sudo firewall-cmd --zone=public --add-masquerade --permanent`	Enable masquerading
`sudo firewall-cmd --zone=public --remove-masquerade --permanent`	Disable masquerading

Logging

Control which denied packets are logged to help with debugging.

Command	Description
`firewall-cmd --get-log-denied`	Show current log-denied setting
`sudo firewall-cmd --set-log-denied=all`	Log all denied packets
`sudo firewall-cmd --set-log-denied=unicast`	Log denied unicast only
`sudo firewall-cmd --set-log-denied=off`	Disable denied-packet logging

Common Server Setup

Baseline rules for a web server using firewalld.

Command	Description
`sudo firewall-cmd --set-default-zone=public`	Set zone to public
`sudo firewall-cmd --zone=public --add-service=ssh --permanent`	Keep SSH access
`sudo firewall-cmd --zone=public --add-service=http --permanent`	Allow HTTP
`sudo firewall-cmd --zone=public --add-service=https --permanent`	Allow HTTPS
`sudo firewall-cmd --reload`	Activate all permanent rules
`firewall-cmd --zone=public --list-all`	Verify active rules

df Cheatsheet

hello@linuxize.com (Linuxize) — Thu, 19 Mar 2026 18:00:00 +0100

Basic Usage

Common ways to check disk space.

Command	Description
`df`	Show disk usage for all mounted filesystems
`df /path`	Show filesystem usage for the given path
`df -h`	Human-readable sizes (K, M, G — powers of 1024)
`df -H`	Human-readable sizes (K, M, G — powers of 1000)
`df -a`	Include all filesystems (including pseudo and duplicate)
`df --total`	Add a grand total row at the bottom

Size Formats

Control how sizes are displayed.

Option	Description
`-h`	Auto-scale using powers of 1024 (`K`, `M`, `G`)
`-H`	Auto-scale using powers of 1000 (SI units)
`-k`	Display sizes in 1K blocks (default on most systems)
`-m`	Display sizes in 1M blocks
`-BG`	Display sizes in 1G blocks
`-B SIZE`	Use SIZE-byte blocks (e.g., `-BM`, `-BG`, `-B512`)

Output Columns

What each column in the default output means.

Column	Description
`Filesystem`	Device or remote path of the filesystem
`1K-blocks` / `Size`	Total size of the filesystem
`Used`	Space currently in use
`Available`	Space available for use
`Use%`	Percentage of space used
`Mounted on`	Directory where the filesystem is mounted

Filesystem Type

Show or filter by filesystem type.

Option	Description
`-T`	Show filesystem type column
`-t TYPE`	Only show filesystems of the given type
`-x TYPE`	Exclude filesystems of the given type
`-l`	Show only local filesystems (exclude network mounts)

Examples:

Command	Description
`df -t ext4`	Show only ext4 filesystems
`df -x tmpfs`	Exclude tmpfs from output
`df -Th`	Show type column with human-readable sizes

Inode Usage

Show inode counts instead of block usage.

Command	Description
`df -i`	Show inode usage for all filesystems
`df -ih`	Show inode usage with human-readable counts
`df -i /path`	Show inode usage for a specific filesystem

Column	Description
`Inodes`	Total number of inodes
`IUsed`	Inodes in use
`IFree`	Inodes available
`IUse%`	Percentage of inodes used

Custom Output Fields

Select specific fields with --output.

Field	Description
`source`	Filesystem device
`fstype`	Filesystem type
`size`	Total size
`used`	Space used
`avail`	Space available
`pcent`	Percentage used
`iused`	Inodes used
`iavail`	Inodes available
`ipcent`	Inode percentage used
`target`	Mount point

Example: df --output=source,size,used,avail,pcent,target -h

Use these references for deeper disk usage workflows.

Guide	Description
`How to Check Disk Space in Linux Using the df Command`	Full `df` guide with practical examples
`Du Command in Linux`	Check disk usage for directories and files

top Cheatsheet

hello@linuxize.com (Linuxize) — Thu, 19 Mar 2026 07:00:00 +0100

Startup Options

Common command-line flags for launching top.

Command	Description
`top`	Start top with default settings
`top -d 5`	Set refresh interval to 5 seconds
`top -n 3`	Exit after 3 screen updates
`top -u username`	Show only processes owned by a user
`top -p 1234,5678`	Monitor specific PIDs
`top -b`	Batch mode (non-interactive, for scripts and logging)
`top -b -n 1`	Print a single snapshot and exit
`top -H`	Show individual threads instead of processes

Key commands available while top is running.

Key	Description
`q`	Quit top
`h` or `?`	Show help screen
`Space`	Refresh the display immediately
`d` or `s`	Change the refresh interval
`k`	Kill a process (prompts for PID and signal)
`r`	Renice a process (change priority)
`u`	Filter by user
`n` or `#`	Set the number of displayed processes
`W`	Save current settings to `~/.toprc`

Sorting

Change the sort column interactively.

Key	Description
`P`	Sort by CPU usage (default)
`M`	Sort by memory usage
`N`	Sort by PID
`T`	Sort by cumulative CPU time
`R`	Reverse the current sort order
`<` / `>`	Move the sort column left / right
`F` or `O`	Open the field management screen to pick a sort column

Display Toggles

Show or hide parts of the summary and task list.

Key	Description
`l`	Toggle the load average line
`t`	Cycle through CPU summary modes (bar, text, off)
`m`	Cycle through memory summary modes (bar, text, off)
`1`	Toggle per-CPU breakdown (one line per core)
`H`	Toggle thread view (show individual threads)
`c`	Toggle between command name and full command line
`V`	Toggle forest (tree) view
`x`	Highlight the current sort column
`z`	Toggle color output

Filtering and Searching

Narrow the process list while top is running.

Key	Description
`u`	Show only processes for a specific user
`U`	Show processes by effective or real user
`o` / `O`	Add a filter (e.g., `COMMAND=nginx` or `%CPU>5.0`)
`Ctrl+O`	Show active filters
`=`	Clear all filters for the current window
`L`	Search for a string in the display
`&`	Find next occurrence of the search string

Summary Area Fields

Key metrics in the header area.

Field	Description
`load average`	System load over 1, 5, and 15 minutes
`us`	CPU time in user space
`sy`	CPU time in kernel space
`ni`	CPU time for niced (reprioritized) processes
`id`	CPU idle time
`wa`	CPU time waiting for I/O
`hi` / `si`	Hardware / software interrupt time
`st`	CPU time stolen by hypervisor (VMs)
`MiB Mem`	Total, free, used, and buffer/cache memory
`MiB Swap`	Total, free, used swap, and available memory

Batch Mode and Logging

Use top in scripts or for capturing snapshots.

Command	Description
`top -b -n 1`	Print one snapshot to stdout
`top -b -n 5 -d 2 > top.log`	Log 5 snapshots at 2-second intervals
`top -b -n 1 -o %MEM`	Single snapshot sorted by memory
`top -b -n 1 -u www-data`	Snapshot of one user’s processes
`top -b -n 1 -p 1234`	Snapshot of a specific PID

Full guides for process monitoring and management.

Guide	Description
`top Command in Linux`	Full `top` guide with examples
`ps Command in Linux`	List and filter processes
`Kill Command in Linux`	Send signals to processes by PID
`Linux Uptime Command`	Check system uptime and load average
`Check Memory in Linux`	Inspect RAM and swap usage

diff Cheatsheet

hello@linuxize.com (Linuxize) — Wed, 18 Mar 2026 08:45:00 +0100

Basic Usage

Compare files and save output.

Command	Description
`diff file1 file2`	Compare two files (normal format)
`diff -u file1 file2`	Unified format (most common)
`diff -c file1 file2`	Context format
`diff -y file1 file2`	Side-by-side format
`diff file1 file2 > file.patch`	Save diff to a patch file

Output Symbols

What each symbol means in the diff output.

Symbol	Format	Meaning
`<`	normal	Line from file1 (removed)
`>`	normal	Line from file2 (added)
`-`	unified/context	Line removed
`+`	unified/context	Line added
`!`	context	Line changed
`@@`	unified	Hunk header with line numbers

Directory Comparison

Compare entire directory trees.

Command	Description
`diff -r dir1 dir2`	Compare directories recursively
`diff -rq dir1 dir2`	Only report which files differ
`diff -rN dir1 dir2`	Treat absent files as empty
`diff -rNu dir1 dir2`	Unified recursive diff (for patches)

Filtering

Ignore specific types of differences.

Option	Description
`-i`	Ignore case differences
`-w`	Ignore all whitespace
`-b`	Ignore changes in whitespace amount
`-B`	Ignore blank lines
`--strip-trailing-cr`	Ignore Windows carriage returns

Common Options

Option	Description
`-u`	Unified format
`-c`	Context format
`-y`	Side-by-side format
`-U n`	Show `n` lines of context (default: 3)
`-C n`	Show `n` lines of context (context format)
`-W n`	Set column width for side-by-side
`-s`	Report when files are identical
`--color`	Colorize output
`-q`	Brief output (only whether files differ)

Patch Workflow

Create and apply patches with diff and patch.

Command	Description
`diff -u file1 file2 > file.patch`	Create a patch for a single file
`diff -rNu dir1 dir2 > dir.patch`	Create a patch for a directory
`patch file1 < file.patch`	Apply patch to file1
`patch -p1 < dir.patch`	Apply directory patch
`patch -R file1 < file.patch`	Reverse (undo) a patch

export Cheatsheet

hello@linuxize.com (Linuxize) — Mon, 16 Mar 2026 09:10:00 +0100

Basic Syntax

Core export command forms in Bash.

Command	Description
`export VAR=value`	Create and export a variable
`export VAR`	Export an existing shell variable
`export -p`	List all exported variables
`export -n VAR`	Remove the export property
`help export`	Show Bash help for `export`

Export Variables

Use export to pass variables to child processes.

Command	Description
`export APP_ENV=production`	Export one variable
`PORT=8080; export PORT`	Define first, export later
`export PATH="$HOME/bin:$PATH"`	Extend `PATH`
`export EDITOR=nano`	Set a default editor
`export LANG=en_US.UTF-8`	Set a locale variable

Export for One Shell Session

These changes last only in the current shell session unless you save them in a startup file.

Command	Description
`export DEBUG=1`	Enable a debug variable for the current session
`export API_URL=https://api.example.com`	Set an application endpoint
`export PATH="$HOME/.local/bin:$PATH"`	Add a per-user bin directory
`echo "$DEBUG"`	Verify that the exported variable is set
`bash -c 'echo "$DEBUG"'`	Confirm the child shell inherits the variable

Export Functions

Bash can export functions to child Bash shells.

Command	Description
`greet() { echo "Hello"; }`	Define a shell function
`export -f greet`	Export a function
`bash -c 'greet'`	Run the exported function in a child shell
`export -nf greet`	Remove the export property from a function

Remove or Reset Exports

Use these commands when you no longer want a variable inherited.

Command	Description
`export -n VAR`	Keep the variable, but stop exporting it
`unset VAR`	Remove the variable completely
`unset -f greet`	Remove a shell function
`export -n PATH`	Stop exporting `PATH` in the current shell
`env	grep ‘^VAR='`

Make Variables Persistent

Add export lines to shell startup files when you want them loaded automatically.

File	Use
`~/.bashrc`	Interactive non-login Bash shells
`~/.bash_profile`	Login Bash shells
`/etc/environment`	System-wide environment variables
`/etc/profile`	System-wide shell startup logic
`source ~/.bashrc`	Reload the current shell after editing

Troubleshooting

Quick checks for common export problems.

Issue	Check
A child process cannot see the variable	Confirm you used `export VAR` or `export VAR=value`
The variable disappears in a new terminal	Add the export line to `~/.bashrc` or another startup file
A function is missing in a child shell	Export it with `export -f name` and use Bash as the child shell
The shell still sees the variable after `export -n`	`export -n` removes inheritance only; use `unset` to remove the variable completely
The variable is set but a command ignores it	Check whether the program reads that variable or expects a config file instead

Use these guides for broader shell and environment-variable workflows.

Guide	Description
export Command in Linux	Full guide to `export` options and examples
How to Set and List Environment Variables in Linux	Broader environment-variable overview
env cheatsheet	Inspect and override environment variables
Bash cheatsheet	Quick reference for Bash syntax and shell behavior

env Cheatsheet

hello@linuxize.com (Linuxize) — Sun, 15 Mar 2026 09:00:00 +0100

Basic Syntax

Core env command forms.

Command	Description
`env`	Print the current environment
`env --help`	Show available options
`env --version`	Show the installed `env` version
`env -0`	Print variables separated with NUL bytes

Inspect Environment Variables

Use env with filters to inspect specific variables.

Command	Description
`env	sort`
`env	grep ‘^PATH='`
`env	grep ‘^HOME='`
`env	grep ‘^LANG='`

Run Commands with Temporary Variables

Set variables for one command without changing the current shell session.

Command	Description
`VAR=value env command`	Run one command with a temporary variable
`VAR1=dev VAR2=1 env command`	Set multiple temporary variables
`env PATH=/custom/bin:$PATH command`	Override `PATH` for one command
`env LANG=C command`	Run a command with the `C` locale
`env HOME=/tmp bash`	Start a shell with a temporary home directory

Clean or Remove Variables

Start with a minimal environment or remove selected variables.

Command	Description
`env -i command`	Run a command with an empty environment
`env -i PATH=/usr/bin:/bin bash --noprofile --norc`	Start a mostly clean shell with a minimal `PATH`
`env -u VAR command`	Run a command without one variable
`env -u http_proxy command`	Remove a proxy variable for one command
`env -i VAR=value command`	Run a command with only the variables you set explicitly

Common Variables

These variables are often inspected or overridden with env.

Variable	Description
`PATH`	Directories searched for commands
`HOME`	Current user’s home directory
`USER`	Current user name
`SHELL`	Default login shell
`LANG`	Locale and language setting
`TZ`	System timezone (e.g. `America/New_York`)
`EDITOR`	Default text editor
`TERM`	Terminal type (e.g. `xterm-256color`)
`TMPDIR`	Directory for temporary files
`PWD`	Current working directory

Troubleshooting

Quick checks for common env issues.

Issue	Check
A temporary variable does not persist	`env VAR=value command` affects only that command and its children
A command is not found after `env -i`	Add a minimal `PATH`, such as `/usr/bin:/bin`
Output is hard to parse safely	Use `env -0` with tools that support NUL-delimited input
A variable is still visible in the shell	`env` does not modify the parent shell; use `export` or unset the variable in the shell itself
A locale-sensitive command behaves differently	Check whether `LANG` or related locale variables were overridden

Use these guides for broader environment-variable workflows.

Guide	Description
How to Set and List Environment Variables in Linux	Full guide to listing and setting environment variables
export Command in Linux	Export shell variables to child processes
Bashrc vs Bash Profile	Understand shell startup files
Bash cheatsheet	Quick reference for Bash syntax and variables

Python Cheatsheet

hello@linuxize.com (Linuxize) — Sat, 14 Mar 2026 08:45:00 +0100

Data Types

Core Python types and how to inspect them.

Syntax	Description
`42`, `3.14`, `-7`	int, float literals
`True`, `False`	bool
`"hello"`, `'world'`	str (immutable)
`[1, 2, 3]`	list — mutable, ordered
`(1, 2, 3)`	tuple — immutable, ordered
`{"a": 1, "b": 2}`	dict — key-value pairs
`{1, 2, 3}`	set — unique, unordered
`None`	Absence of a value
`type(x)`	Get type of `x`
`isinstance(x, int)`	Check if `x` is of a given type

Operators

Arithmetic, comparison, logical, and membership operators.

Operator	Description
`+`, `-`, `*`, `/`	Add, subtract, multiply, divide
`//`	Floor division
`%`	Modulo (remainder)
`**`	Exponentiation
`==`, `!=`	Equal, not equal
`<`, `>`, `<=`, `>=`	Comparison
`and`, `or`, `not`	Logical operators
`in`, `not in`	Membership test
`is`, `is not`	Identity test
`x if cond else y`	Ternary (conditional) expression

String Methods

Common operations on str objects. Strings are immutable — methods return a new string.

Method	Description
`s.upper()` / `s.lower()`	Convert to upper / lowercase
`s.strip()`	Remove leading and trailing whitespace
`s.lstrip()` / `s.rstrip()`	Remove leading / trailing whitespace
`s.split(",")`	Split on delimiter, return list
`",".join(lst)`	Join list elements into a string
`s.replace("old", "new")`	Replace all occurrences
`s.find("x")`	First index of substring (-1 if not found)
`s.startswith("x")`	`True` if string starts with prefix
`s.endswith("x")`	`True` if string ends with suffix
`s.count("x")`	Count non-overlapping occurrences
`s.isdigit()` / `s.isalpha()`	Check all digits / all letters
`len(s)`	String length
`s[i]`, `s[i:j]`, `s[::step]`	Index, slice, step
`"x" in s`	Substring membership test

String Formatting

Embed values in strings.

Syntax	Description
`f"Hello, {name}"`	f-string (Python 3.6+)
`f"{val:.2f}"`	Float with 2 decimal places
`f"{val:>10}"`	Right-align in 10 characters
`f"{val:,}"`	Thousands separator
`f"{{name}}"`	Literal braces in output
`"Hello, {}".format(name)`	str.format()
`"Hello, %s" % name`	%-formatting (legacy)

List Methods

Common operations on list objects.

Method	Description
`lst.append(x)`	Add element to end
`lst.extend([x, y])`	Add multiple elements to end
`lst.insert(i, x)`	Insert element at index `i`
`lst.remove(x)`	Remove first occurrence of `x`
`lst.pop()`	Remove and return last element
`lst.pop(i)`	Remove and return element at index `i`
`lst.index(x)`	First index of `x`
`lst.count(x)`	Count occurrences of `x`
`lst.sort()`	Sort in place (ascending)
`lst.sort(reverse=True)`	Sort in place (descending)
`lst.reverse()`	Reverse in place
`lst.copy()`	Shallow copy
`lst.clear()`	Remove all elements
`len(lst)`	List length
`lst[i]`, `lst[i:j]`	Index and slice
`x in lst`	Membership test

Dictionary Methods

Common operations on dict objects.

Method	Description
`d[key]`	Get value by key (raises `KeyError` if missing)
`d.get(key)`	Get value or `None` if key not found
`d.get(key, default)`	Get value or default if key not found
`d[key] = val`	Set or update a value
`del d[key]`	Delete a key
`d.pop(key)`	Remove key and return its value
`d.keys()`	View of all keys
`d.values()`	View of all values
`d.items()`	View of all (key, value) pairs
`d.update(d2)`	Merge another dict into `d`
`d.setdefault(key, val)`	Set key if missing, return value
`key in d`	Check if key exists
`len(d)`	Number of key-value pairs
`{d1, d2}`	Merge dicts (Python 3.9+: `d1 \| d2`)

Sets

Common operations on set objects.

Syntax	Description
`set()`	Empty set (use this, not `{}`)
`s.add(x)`	Add element
`s.remove(x)`	Remove element (raises `KeyError` if missing)
`s.discard(x)`	Remove element (no error if missing)
`s1 \| s2`	Union
`s1 & s2`	Intersection
`s1 - s2`	Difference
`s1 ^ s2`	Symmetric difference
`s1 <= s2`	Subset check
`x in s`	Membership test

Control Flow

Conditionals, loops, and flow control keywords.

Syntax	Description
`if cond:` / `elif cond:` / `else:`	Conditional blocks
`for item in iterable:`	Iterate over a sequence
`for i, v in enumerate(lst):`	Iterate with index and value
`while cond:`	Loop while condition is true
`break`	Exit loop immediately
`continue`	Skip to next iteration
`pass`	No-op placeholder
`match x:` / `case val:`	Pattern matching (Python 3.10+)

Functions

Define and call functions.

Syntax	Description
`def func(x, y):`	Define a function
`return val`	Return a value
`def func(x=0):`	Default argument
`def func(*args):`	Variable positional arguments
`def func(**kwargs):`	Variable keyword arguments
`lambda x: x * 2`	Anonymous (lambda) function
`func(y=1, x=2)`	Call with keyword arguments
`result = func(x)`	Call and capture return value

File I/O

Open, read, and write files.

Syntax	Description
`open("f.txt", "r")`	Open for reading (default mode)
`open("f.txt", "w")`	Open for writing — creates or overwrites
`open("f.txt", "a")`	Open for appending
`open("f.txt", "rb")`	Open for reading in binary mode
`with open("f.txt") as f:`	Open with context manager (auto-close)
`f.read()`	Read entire file as a string
`f.read(n)`	Read `n` characters
`f.readline()`	Read one line
`f.readlines()`	Read all lines into a list
`for line in f:`	Iterate over lines
`f.write("text")`	Write string to file
`f.writelines(lst)`	Write list of strings

Exception Handling

Catch and handle runtime errors.

Syntax	Description
`try:`	Start guarded block
`except ValueError:`	Catch a specific exception
`except (TypeError, ValueError):`	Catch multiple exception types
`except Exception as e:`	Catch and bind exception to variable
`else:`	Run if no exception was raised
`finally:`	Always run — use for cleanup
`raise ValueError("msg")`	Raise an exception
`raise`	Re-raise the current exception

Comprehensions

Build lists, dicts, sets, and generators in one expression.

Syntax	Description
`[x for x in lst]`	List comprehension
`[x for x in lst if cond]`	Filtered list comprehension
`[f(x) for x in range(n)]`	Comprehension with expression
`{k: v for k, v in d.items()}`	Dict comprehension
`{x for x in lst}`	Set comprehension
`(x for x in lst)`	Generator expression (lazy)

Useful Built-ins

Frequently used Python built-in functions.

Function	Description
`print(x)`	Print to stdout
`input("prompt")`	Read user input as string
`len(x)`	Length of sequence or collection
`range(n)` / `range(a, b, step)`	Integer sequence
`enumerate(lst)`	(index, value) pairs
`zip(a, b)`	Pair elements from two iterables
`map(func, lst)`	Apply function to each element
`filter(func, lst)`	Filter elements by predicate
`sorted(lst)`	Return sorted copy
`sum(lst)`, `min(lst)`, `max(lst)`	Sum, minimum, maximum
`abs(x)`, `round(x, n)`	Absolute value, round to `n` places
`int(x)`, `float(x)`, `str(x)`	Type conversion

Guide	Description
Python f-Strings	String formatting with f-strings
Python Lists	List operations and methods
Python Dictionaries	Dictionary operations and methods
Python for Loop	Iterating with for loops
Python while Loop	Looping with while
Python if/else Statement	Conditionals and branching
How to Replace a String in Python	String replacement methods
How to Split a String in Python	Splitting strings into lists

kill Cheatsheet

hello@linuxize.com (Linuxize) — Fri, 13 Mar 2026 07:25:00 +0100

Basic Syntax

Core kill command forms.

Command	Description
`kill PID`	Send `SIGTERM` (graceful stop) to a process
`kill -9 PID`	Force kill a process (`SIGKILL`)
`kill -1 PID`	Reload process config (`SIGHUP`)
`kill -l`	List all available signal names and numbers
`kill -0 PID`	Check if a PID exists without sending a signal

Signal Reference

Signals most commonly used with kill, killall, and pkill.

Signal	Number	Description
`SIGHUP`	`1`	Reload config — most daemons reload settings without restarting
`SIGINT`	`2`	Interrupt process — equivalent to pressing `Ctrl+C`
`SIGQUIT`	`3`	Quit and write a core dump for debugging
`SIGKILL`	`9`	Force kill — cannot be caught or ignored; always terminates immediately
`SIGTERM`	`15`	Graceful stop — default signal; process can clean up before exiting
`SIGUSR1`	`10`	User-defined signal 1 — meaning depends on the application
`SIGUSR2`	`12`	User-defined signal 2 — meaning depends on the application
`SIGCONT`	`18`	Resume a process that was suspended with `SIGSTOP`
`SIGSTOP`	`19`	Suspend process — cannot be caught or ignored
`SIGTSTP`	`20`	Terminal stop — equivalent to pressing `Ctrl+Z`

Kill by PID

Send signals to one or more specific processes.

Command	Description
`kill 1234`	Gracefully stop PID `1234`
`kill -9 1234 5678`	Force kill multiple PIDs at once
`kill -HUP 1234`	Reload config for PID `1234`
`kill -STOP 1234`	Suspend PID `1234`
`kill -CONT 1234`	Resume suspended PID `1234`
`kill -9 $(pidof firefox)`	Force kill all PIDs for a process by name

killall: Kill by Name

Send signals to all processes matching an exact name.

Command	Description
`killall process_name`	Send `SIGTERM` to all matching processes
`killall -9 process_name`	Force kill all matching processes
`killall -HUP nginx`	Reload all `nginx` processes
`killall -u username process_name`	Kill matching processes owned by a user
`killall -v process_name`	Kill and report which processes were signaled
`killall -r "pattern"`	Match process names with a regex pattern

Background Jobs

Kill jobs running in the current shell session.

Command	Description
`jobs`	List background jobs and their job numbers
`kill %1`	Send `SIGTERM` to background job number `1`
`kill -9 %1`	Force kill background job number `1`
`kill %+`	Kill the most recently started background job
`kill %%`	Kill the current (most recent) background job

Troubleshooting

Quick fixes for common kill issues.

Issue	Check
Process does not stop after `SIGTERM`	Wait a moment, then escalate to `kill -9 PID`
`No such process` error	PID has already exited; verify with `ps -p PID`
`Operation not permitted`	Process belongs to another user — use `sudo kill PID`
`SIGKILL` has no effect	Process is in uninterruptible sleep (`D` state in `ps`); only a reboot can free it
Not sure which PID to kill	Find it first with `pidof name`, `pgrep name`, or `ps aux \| grep name`

Guide	Description
kill Command in Linux	Full guide to kill options, signals, and examples
How to Kill a Process in Linux	Practical walkthrough for finding and stopping processes
pkill Command in Linux	Kill processes by name and pattern
pgrep Command in Linux	Find process PIDs before signaling
ps Command in Linux	Inspect the running process list

watch Cheatsheet

hello@linuxize.com (Linuxize) — Thu, 12 Mar 2026 10:40:00 +0100

Basic Syntax

Core watch command forms.

Command	Description
`watch command`	Run a command repeatedly every 2 seconds
`watch -n 5 command`	Refresh every 5 seconds
`watch -n 1 date`	Update output every second
`watch --help`	Show available options

Common Monitoring Tasks

Use watch to keep an eye on changing system state.

Command	Description
`watch free -h`	Monitor memory usage
`watch df -h`	Monitor disk space
`watch uptime`	Check load averages and uptime
`watch “ps -ef	grep nginx”`
`watch "ss -tulpn"`	Monitor listening sockets

Timing and Refresh Control

Control how often watch reruns the command.

Command	Description
`watch -n 0.5 command`	Refresh every 0.5 seconds
`watch -n 10 command`	Refresh every 10 seconds
`watch -t command`	Hide the header line
`watch -p command`	Try to run at precise intervals
`watch -x command arg1 arg2`	Run the command directly without `sh -c`

Highlighting Changes

Make changing output easier to spot.

Command	Description
`watch -d command`	Highlight differences between updates
`watch -d free -h`	Highlight memory changes
`watch -d "ip -brief address"`	Highlight interface state or address changes
`watch -d -n 1 "cat /proc/loadavg"`	Highlight load-average changes

Commands with Pipes and Quotes

Wrap pipelines and shell syntax in quotes unless you use -x.

Command	Description
`watch “ps -ef	grep apache”`
`watch “ls -lh /var/log	tail”`
`watch "grep -c error /var/log/syslog"`	Count matching lines repeatedly
`watch -x ls -lh /var/log`	Run `ls` directly without shell parsing
`watch “find /tmp -maxdepth 1 -type f	wc -l”`

Exit Conditions and Beeps

Stop or alert when output changes.

Command	Description
`watch -g command`	Exit when command output changes
`watch -b command`	Beep if the command exits with non-zero status
`watch -b -n 5 "systemctl is-active nginx"`	Alert if the service is no longer active
`watch -g "cat /tmp/status.txt"`	Exit when the file content changes

Troubleshooting

Quick fixes for common watch issues.

Issue	Check
Pipes or redirects do not work	Quote the whole command or use `sh -c`
The screen flickers too much	Increase the interval or hide the header with `-t`
Output changes are hard to spot	Add `-d` to highlight differences
The command exits immediately	Check the command syntax outside `watch` first
You need shell expansion and variables	Use quoted shell commands instead of `-x`

Use these guides for broader monitoring and process tasks.

Guide	Description
Linux Watch Command	Full guide to `watch` options and examples
ps Command in Linux	Inspect running processes
free Command in Linux	Check memory usage
ss Command in Linux	Inspect sockets and ports
top Command in Linux	Monitor processes interactively

tcpdump Cheatsheet

hello@linuxize.com (Linuxize) — Tue, 10 Mar 2026 08:20:00 +0100

Basic Syntax

Core tcpdump command forms.

Command	Description
`sudo tcpdump`	Start capturing on the default interface
`sudo tcpdump -i eth0`	Capture on a specific interface
`sudo tcpdump -i any`	Capture on all interfaces
`sudo tcpdump -D`	List available interfaces
`sudo tcpdump -h`	Show help and usage

Limit and Format Output

Control how much data is shown and how packets are displayed.

Command	Description
`sudo tcpdump -c 10`	Stop after 10 packets
`sudo tcpdump -n`	Do not resolve hostnames
`sudo tcpdump -nn`	Do not resolve hostnames or service names
`sudo tcpdump -v`	Verbose output
`sudo tcpdump -X`	Show packet contents in hex and ASCII

Protocol Filters

Capture only the protocol traffic you care about.

Command	Description
`sudo tcpdump tcp`	Capture TCP packets only
`sudo tcpdump udp`	Capture UDP packets only
`sudo tcpdump icmp`	Capture ICMP packets only
`sudo tcpdump arp`	Capture ARP traffic
`sudo tcpdump port 53`	Capture DNS traffic on port 53

Host and Port Filters

Match packets by source, destination, host, or port.

Command	Description
`sudo tcpdump host 192.168.1.10`	Capture traffic to or from one host
`sudo tcpdump src host 192.168.1.10`	Capture packets from one source host
`sudo tcpdump dst host 192.168.1.10`	Capture packets to one destination host
`sudo tcpdump port 22`	Capture SSH traffic
`sudo tcpdump src port 443`	Capture packets from source port 443

Combine Filters

Use boolean operators to build precise capture expressions.

Command	Description
`sudo tcpdump 'tcp and port 80'`	Capture HTTP traffic over TCP
`sudo tcpdump 'host 10.0.0.5 and port 22'`	Capture SSH traffic for one host
`sudo tcpdump 'src 10.0.0.5 and dst port 443'`	Match one source and HTTPS destination
`sudo tcpdump 'port 80 or port 443'`	Capture HTTP or HTTPS traffic
`sudo tcpdump 'net 192.168.1.0/24 and not port 22'`	Capture a subnet except SSH

Write and Read Capture Files

Save traffic to a file or inspect an existing pcap capture.

Command	Description
`sudo tcpdump -w capture.pcap`	Write packets to a pcap file
`sudo tcpdump -r capture.pcap`	Read packets from a pcap file
`sudo tcpdump -i eth0 -w web.pcap port 80`	Save filtered traffic to a file
`sudo tcpdump -nn -r capture.pcap`	Read a file without name resolution
`sudo tcpdump -r capture.pcap 'host 10.0.0.5'`	Apply a filter while reading a pcap

Common Use Cases

Practical commands for day-to-day packet inspection.

Command	Description
`sudo tcpdump -i any port 22`	Watch SSH connections
`sudo tcpdump -i any port 53`	Inspect DNS queries and replies
`sudo tcpdump -i eth0 host 8.8.8.8`	Trace traffic to one external host
`sudo tcpdump -i any 'tcp port 80 or tcp port 443'`	Watch web traffic
`sudo tcpdump -i any icmp`	Check ping and ICMP traffic

Troubleshooting

Quick checks for common tcpdump issues.

Issue	Check
`You do not have permission to capture on that device`	Run with `sudo` or verify packet-capture capabilities
No packets appear	Confirm the correct interface with `tcpdump -D` and use `-i any` if needed
Hostnames make output slow	Add `-n` or `-nn` to disable name resolution
Output is too noisy	Add `-c`, protocol filters, or host/port filters to narrow the capture
Need to inspect later	Write to a file with `-w capture.pcap` and review it with `tcpdump -r` or Wireshark

Use these guides for broader networking and packet-capture workflows.

Guide	Description
tcpdump Command in Linux	Full `tcpdump` guide with detailed examples
ss Command in Linux	Inspect sockets and listening services
ping cheatsheet	Test reachability and latency
IP command cheatsheet	Check interfaces, addresses, and routes
How to Check Open Ports in Linux	Review listening ports before capturing traffic

su Cheatsheet

hello@linuxize.com (Linuxize) — Tue, 10 Mar 2026 08:10:00 +0100

Basic Syntax

Core su command forms.

Command	Description
`su`	Switch to root using the current shell environment
`su -`	Switch to root with a full login shell
`su username`	Switch to another user
`su - username`	Switch to another user with a login shell
`su --help`	Show available options

Choose whether to keep the current environment or start a clean login session.

Command	Description
`su`	Keep most of the current environment
`su -`	Load the target user’s login environment
`su - username`	Change to the target user’s home directory and shell
`whoami`	Confirm the current effective user
`pwd`	Check whether the working directory changed

Run a Command as Another User

Use -c to run a single command without starting a full interactive shell.

Command	Description
`su -c 'whoami'`	Run a single command as root
`su -c 'id' username`	Run a command as another user
`su -c 'ps aux'`	Run a quoted command with spaces
`su -c 'cd /tmp && pwd' username`	Run a compound shell command
`su -c 'echo $HOME' username`	Check the target user’s home in a non-login shell

Shell and Environment

Adjust the shell or preserve the caller’s environment when needed.

Command	Description
`su -s /bin/bash username`	Use Bash as the target shell
`su -s /usr/bin/zsh username`	Use Zsh as the target shell
`su -p`	Preserve the current environment
`echo $HOME`	Check the current home directory
`echo $SHELL`	Check the current shell

Root Access Patterns

Compare common root-shell workflows.

Command	Description
`su`	Prompt for the root password
`su -`	Prompt for the root password and start a login shell
`sudo su -`	Use `sudo` to start a root login shell
`sudo -i`	Start a root login shell without calling `su` directly
`exit`	Leave the current `su` shell

Troubleshooting

Quick checks for common su issues.

Issue	Check
`Authentication failure`	Verify the target user’s password, not your own
`su: user username does not exist`	Confirm the account exists with `id username`
`This account is currently not available`	Check the target shell in `/etc/passwd`; service accounts often use `/usr/sbin/nologin`
`su` keeps the old `PATH`	Use `su -` to start a clean login shell
Root access fails on Ubuntu	The root account may be locked; use `sudo -i` instead

Use these guides when working with users, passwords, and privilege escalation.

Guide	Description
su Command in Linux	Full `su` guide with examples and `sudo` comparison
sudo Command in Linux	Run commands with elevated privileges
How to Change User Password in Linux	Set or reset passwords
useradd cheatsheet	Create and manage user accounts
How to Add User to Group in Linux	Manage group membership

ping Cheatsheet

hello@linuxize.com (Linuxize) — Mon, 09 Mar 2026 08:40:00 +0100

Basic Syntax

Core ping command forms.

Command	Description
`ping host`	Continuously ping a host
`ping -c 4 host`	Send 4 echo requests, then stop
`ping -i 2 host`	Wait 2 seconds between packets
`ping -w 10 host`	Stop after 10 seconds
`ping --help`	Show available options

Common Reachability Checks

Quick tests for DNS names and IP addresses.

Command	Description
`ping google.com`	Test DNS resolution and connectivity
`ping 8.8.8.8`	Test reachability to a public IPv4 address
`ping localhost`	Verify local TCP/IP stack
`ping $(hostname -I	awk ‘{print $1}’)`
`ping router.local`	Test a local network device by hostname

Count and Timing

Control how many packets are sent and how long ping runs.

Command	Description
`ping -c 3 host`	Send exactly 3 packets
`ping -c 5 -i 0.5 host`	Send 5 packets at 0.5-second intervals
`ping -w 5 host`	Stop after 5 seconds total
`ping -W 2 host`	Wait up to 2 seconds for each reply
`ping -c 10 -q host`	Show summary only after 10 packets

IPv4 and IPv6

Force the address family when needed.

Command	Description
`ping -4 host`	Use IPv4 only
`ping -6 host`	Use IPv6 only
`ping6 host`	IPv6 ping on systems that provide `ping6`
`ping -c 4 -4 example.com`	Check IPv4 replies for a dual-stack host
`ping -c 4 -6 example.com`	Check IPv6 replies for a dual-stack host

Packet Size and Interface

Adjust packet payload and source interface.

Command	Description
`ping -s 1400 host`	Send larger packets with 1400-byte payload
`ping -s 56 host`	Use the default payload size explicitly
`ping -I eth0 host`	Send packets from a specific interface
`ping -I 192.168.1.10 host`	Use a specific source address
`ping -D host`	Print timestamps before each reply

Troubleshooting

Quick checks for common ping issues.

Issue	Check
`Name or service not known`	DNS failed; test with an IP address directly
`Destination Host Unreachable`	Check routing, gateway, and local network link
100% packet loss	The host may be down, blocked by a firewall, or not routing replies
`ping: socket: Operation not permitted`	Use `sudo` or verify capabilities on systems with restricted raw sockets
IPv6 ping fails only	Confirm the host has AAAA records and IPv6 connectivity

Use these guides for broader network troubleshooting workflows.

Guide	Description
ping Command in Linux	Full `ping` guide with detailed examples
IP command cheatsheet	Inspect interfaces, addresses, and routes
ss Command in Linux	Inspect sockets and active network connections
traceroute Command in Linux	Trace the route packets take to a host
SSH cheatsheet	Quick reference for remote connectivity commands

xargs Cheatsheet

hello@linuxize.com (Linuxize) — Sun, 08 Mar 2026 08:10:00 +0100

Basic Syntax

Core xargs command forms.

Command	Description
`xargs command`	Read stdin and pass items to a command
`printf '%s\n' a b c \| xargs command`	Pass newline-separated items to a command
`cat list.txt \| xargs command`	Read arguments from a file through stdin
`xargs`	Use `/bin/echo` as the default command
`xargs --help`	Show available options

Limit Arguments

Control how many items xargs passes at a time.

Command	Description
`printf '%s\n' a b c \| xargs -n 1 echo`	Pass one argument per command run
`printf '%s\n' a b c d \| xargs -n 2 echo`	Pass two arguments per command run
`printf '%s\n' a b c \| xargs -L 1 echo`	Read one input line per command run
`printf '%s\n' a b c \| xargs -P 4 echo`	Run up to four commands in parallel
`printf '%s\n' a b c \| xargs -n 100 rm`	Batch large argument lists

Replace Input

Use placeholders when each input item must appear in a specific position.

Command	Description
`printf '%s\n' file1 file2 \| xargs -I {} touch {}`	Replace `{}` with each input item
`printf '%s\n' file1 file2 \| xargs -I % sh -c 'echo %; ls -l %'`	Run multiple commands per item
`printf '%s\n' img1 img2 \| xargs -I {} mv {} {}.bak`	Reuse the same item twice
`printf '%s\n' user1 user2 \| xargs -I {} id {}`	Insert input into a fixed command pattern
`printf '%s\n' src1 src2 \| xargs -I {} cp {} /backup/`	Copy each input item to a directory

Safe File Handling

Use null-delimited input when paths may contain spaces or special characters.

Command	Description
`find . -type f -print0 \| xargs -0 rm -f`	Remove found files safely
`find . -name '*.log' -print0 \| xargs -0 ls -lh`	List matching files safely
`find . -type f -print0 \| xargs -0 -n 1 basename`	Process one safe path at a time
`printf '%s\0' 'file one' 'file two' \| xargs -0 -n 1 echo`	Feed null-delimited names directly
`find /var/www -type f -print0 \| xargs -0 chmod 644`	Apply permissions to many files safely

Preview and Confirm

Check generated commands before running them.

Command	Description
`printf '%s\n' a b c \| xargs -t touch`	Print each command before execution
`printf '%s\n' a b c \| xargs -p rm`	Prompt before running the command
`find . -type f -print0 \| xargs -0 -t rm -f`	Preview destructive file removals
`find . -type f -print0 \| xargs -0 echo rm -f`	Dry run by replacing `rm` with `echo`
`printf '%s\n' a b c \| xargs -r echo`	Do nothing if stdin is empty

Read from Files

Load items from a file instead of a pipeline.

Command	Description
`xargs -a list.txt echo`	Read arguments from `list.txt`
`xargs -a ips.txt -L 1 ping -c 1`	Read one IP per line and ping it
`xargs -a packages.txt sudo apt install`	Install packages listed in a file
`xargs -a dirs.txt mkdir -p`	Create directories from a file
`xargs -a users.txt -n 1 id`	Check users listed in a file

Troubleshooting

Quick checks for common xargs issues.

Issue	Check
Filenames split at spaces	Use `find -print0 \| xargs -0`
Too many arguments at once	Add `-n N` to batch input
Command order looks wrong	Add `-t` to print generated commands
Empty input still runs command	Use `-r` to skip empty stdin
Need item in the middle of a command	Use `-I {}` with a placeholder

Use these guides for full command workflows.

Guide	Description
xargs Command in Linux	Full `xargs` tutorial with practical examples
find Files in Linux	Build file lists to pass into `xargs`
rm Command in Linux	Remove files safely in bulk operations
grep Command in Linux	Filter text before passing results to `xargs`
Bash Cheatsheet	Shell patterns for scripts and pipelines

wc Cheatsheet

hello@linuxize.com (Linuxize) — Sat, 07 Mar 2026 08:55:00 +0100

Basic Syntax

Core wc command forms.

Command	Description
`wc file.txt`	Show lines, words, and bytes for a file
`wc file1 file2`	Show counts per file and a total line
`wc *.log`	Count all matching files
`command \| wc`	Count output from another command
`wc --help`	Show available options

Common Count Flags

Use flags to request specific counters.

Command	Description
`wc -l file.txt`	Count lines only
`wc -w file.txt`	Count words only
`wc -c file.txt`	Count bytes only
`wc -m file.txt`	Count characters only
`wc -L file.txt`	Show longest line length

Useful Pipelines

Practical wc combinations for quick shell checks.

Command	Description
`ls -1 \| wc -l`	Count directory entries (one per line)
`grep -r "ERROR" /var/log \| wc -l`	Count matching log lines
`find . -type f \| wc -l`	Count files recursively
`ps aux \| wc -l`	Count process list lines
`cat file.txt \| wc -w`	Count words from stdin

Multi-File Counting

Summarize multiple files and totals.

Command	Description
`wc -l *.txt`	Line count for each file plus total
`wc -w docs/*.md`	Word count per Markdown file and total
`wc -c part1 part2 part3`	Byte count per file and combined total
`wc -m *.csv`	Character count for each CSV file
`wc -L *.log`	Max line length per file and max total

Script-Friendly Patterns

Extract numeric output safely in scripts.

Command	Description
`count=$(wc -l < file.txt)`	Capture pure line count without filename
`words=$(wc -w < file.txt)`	Capture word count only
`bytes=$(wc -c < file.txt)`	Capture byte count only
`if [ "$(wc -l < file.txt)" -gt 1000 ]; then ... fi`	Threshold check in scripts
`printf '%s\n' "$text" \| wc -m`	Count characters in a variable

Troubleshooting

Quick checks for common wc confusion.

Issue	Check
Count includes filename	Use input redirection: `wc -l < file`
Unexpected word count	Confirm whitespace and delimiters in the file
Character and byte counts differ	Use `-m` for characters and `-c` for bytes
Total line missing with many files	Ensure shell glob matches at least one file
Pipeline count seems off by one	Some commands add headers; account for that

Use these guides for complete text-processing workflows.

Guide	Description
linux wc Command	Full `wc` guide with detailed examples
head Command in Linux	Show first lines of files
tail Command in Linux	Show last lines and follow logs
grep Command in Linux	Search and filter matching lines
find Files in Linux	Build file lists for counting

useradd Cheatsheet

hello@linuxize.com (Linuxize) — Fri, 06 Mar 2026 14:30:00 +0100

Basic Syntax

Core useradd command forms.

Command	Description
`sudo useradd username`	Create a user account with defaults
`sudo useradd -m username`	Create user and home directory
`sudo useradd -m -s /bin/bash username`	Create user with explicit login shell
`sudo useradd -m -c "Full Name" username`	Create user with GECOS/comment field
`sudo useradd -D`	Show current default `useradd` settings

Home Directory and Shell

Set home path and login shell at creation time.

Command	Description
`sudo useradd -m username`	Create `/home/username` if missing
`sudo useradd -M username`	Create user without home directory
`sudo useradd -d /srv/appuser -m appuser`	Create user with custom home path
`sudo useradd -s /bin/zsh username`	Set login shell to Zsh
`sudo useradd -s /usr/sbin/nologin serviceuser`	Disable interactive login for service account

Groups and Permissions

Assign primary and supplementary groups during creation.

Command	Description
`sudo useradd -m -g developers username`	Set primary group to `developers`
`sudo useradd -m -G sudo username`	Add user to supplementary `sudo` group
`sudo useradd -m -G docker,developers username`	Add user to multiple supplementary groups
`id username`	Verify UID, GID, and group membership
`groups username`	Show group memberships for a user

UID, Expiry, and Inactive Policy

Control account identity and lifetime.

Command	Description
`sudo useradd -m -u 1050 username`	Create user with specific UID
`sudo useradd -m -e 2026-12-31 username`	Set account expiration date
`sudo useradd -m -f 30 username`	Disable account after 30 inactive days
`sudo useradd -m -k /etc/skel username`	Use skeleton directory for initial files
`sudo chage -l username`	Inspect account aging and expiry policy

Password and Account Activation

Set password and verify account usability.

Command	Description
`sudo passwd username`	Set or reset user password
`sudo passwd -l username`	Lock account password login
`sudo passwd -u username`	Unlock account password login
`sudo su - username`	Test login environment for new user
`getent passwd username`	Confirm user entry in account database

Defaults and Safe Workflow

Check defaults first and validate each account creation.

Command	Description
`sudo useradd -D`	Show defaults (`HOME`, `SHELL`, `SKEL`, etc.)
`sudo useradd -D -s /bin/bash`	Change default shell for future users
`sudo useradd -m newuser && sudo passwd newuser`	Common two-step creation flow
`sudo usermod -aG sudo newuser`	Grant admin privileges after creation
`sudo userdel -r username`	Remove user and home directory when deprovisioning

Troubleshooting

Quick checks for common useradd errors.

Issue	Check
`useradd: user 'name' already exists`	Confirm with `id name` or choose a different username
`group 'name' does not exist`	Create group first with `groupadd` or use an existing group
Home directory not created	Use `-m` and verify defaults with `useradd -D`
Cannot log in after creation	Check shell (`getent passwd user`) and set password with `passwd`
UID conflict	Verify used UIDs in `/etc/passwd` before assigning `-u` manually

Use these guides for full account lifecycle tasks.

Guide	Description
How to Create Users in Linux Using the useradd Command	Full `useradd` tutorial with examples
usermod Command in Linux	Modify existing user accounts
How to Delete Users in Linux Using userdel	Remove users safely
How to Add User to Group in Linux	Manage supplementary groups
How to Change User Password in Linux	Set and rotate account passwords

less Cheatsheet

hello@linuxize.com (Linuxize) — Thu, 05 Mar 2026 08:20:00 +0100

Basic Usage

Common ways to open files and piped output in less.

Command	Description
`less file.txt`	Open a file in the pager
`less /var/log/syslog`	Read a system log file
`command \| less`	Pipe command output into `less`
`less +G file.txt`	Open a file and jump to the end
`less +/pattern file.txt`	Open a file and jump to first match

Move through content quickly in the pager.

Key	Description
`Space`	Move forward one page
`b`	Move backward one page
`Enter`	Move forward one line
`k` / `y`	Move backward one line
`d` / `u`	Move forward / backward half a page
`g`	Jump to top of file
`G`	Jump to bottom of file
`50g`	Jump to line 50
`F`	Follow mode — stream new content as it is appended (press `Ctrl+C` to stop)
`q`	Quit `less`

Find text and move between matches.

Key	Description
`/pattern`	Search forward for `pattern`
`?pattern`	Search backward for `pattern`
`n`	Next match in current search direction
`N`	Previous match in current search direction
`&pattern`	Show only lines matching `pattern`
`&` (empty)	Clear `&pattern` filtered view

Useful Options

Flags that improve readability in daily use.

Command	Description
`less -N file.txt`	Show line numbers
`less -S file.txt`	Disable line wrap (horizontal scrolling)
`less -R file.txt`	Show ANSI colors in output
`less -i file.txt`	Case-insensitive search by default
`less -F file.txt`	Quit automatically if content fits one screen
`less -X file.txt`	Keep screen content after quitting

Log and Output Workflows

Practical examples for troubleshooting and analysis.

Command	Description
`less +F /var/log/syslog`	Follow a log file live (like `tail -f`); press `Ctrl+C` to stop and search
`journalctl -xe \| less`	Page through recent systemd logs
`dmesg \| less`	Inspect kernel messages page by page
`ps aux \| less`	Browse long process listings
`git log \| less`	Read long commit history safely
`grep -R \"ERROR\" /var/log \| less`	Review search results interactively

Troubleshooting

Quick fixes for common less issues.

Issue	Check
Search does not find expected text	Retry with exact case or use `-i` for case-insensitive search
Color codes look broken	Use `less -R` when input includes ANSI colors
Lines wrap and are hard to read	Use `less -S` and move sideways with arrow keys
Pager exits immediately	Content may fit one screen; remove `-F` if you need manual paging
You opened from pipe and lost context	Rerun command with `\| less` and search using `/pattern`

Use these guides for deeper command and text-processing workflows.

Guide	Description
less Command in Linux	Full `less` tutorial with examples
head Command in Linux	Show the first lines of files
tail Command in Linux	Follow file growth and recent lines
grep Command in Linux	Search text patterns in files
wc Command in Linux	Count lines, words, and bytes

pkill Cheatsheet

hello@linuxize.com (Linuxize) — Tue, 03 Mar 2026 15:00:00 +0100

Basic Syntax

Core pkill command forms.

Command	Description
`pkill process_name`	Send `SIGTERM` to matching process names
`pkill -f "pattern"`	Match against full command line
`pkill -u username process_name`	Match only processes owned by a user
`pkill -x process_name`	Match exact process name only
`pkill -l process_name`	Kill matching processes and print their name and PID

Common Signals

Frequently used signals with pkill.

Command	Description
`pkill -15 process_name`	Graceful stop (`SIGTERM`, default)
`pkill -9 process_name`	Force kill (`SIGKILL`)
`pkill -HUP process_name`	Reload/reopen config for daemons
`pkill -INT process_name`	Interrupt process (`SIGINT`)
`pkill -USR1 process_name`	Send user-defined signal 1

Match Controls

Limit matches to avoid terminating the wrong process.

Command	Description
`pkill -x nginx`	Kill only exact `nginx` process name
`pkill -f "python3 app.py"`	Match a specific command string
`pkill -u deploy -x node`	Match exact `node` only for user `deploy`
`pkill -t pts/2`	Match processes attached to terminal `pts/2`
`pkill -P 1234`	Match child processes of PID `1234`

Safer Workflow

Preview targets before signaling processes.

Command	Description
`pgrep -a nginx`	Preview matching processes and command lines
`pgrep -afu deploy node`	Preview user-scoped full-command matches
`pgrep -f "python3 app.py"`	Confirm full-pattern matches first
`pkill -x nginx`	Execute only after preview validation
`echo $?`	Check exit code (`0` match found, `1` none found)

Service and App Examples

Practical process control patterns.

Command	Description
`pkill -HUP nginx`	Ask Nginx master process to reload
`pkill -u www-data -x php-fpm`	Stop `php-fpm` workers for one user
`pkill -f "gunicorn: worker"`	Signal Gunicorn worker processes
`pkill -f "node server.js"`	Stop a specific Node.js app instance
`pkill -x firefox`	Close all Firefox processes for current user

Troubleshooting

Quick checks for common pkill issues.

Issue	Check
Nothing happened	Verify matches with `pgrep -a` using the same pattern
Wrong process was terminated	Use `-x` or stricter `-f` pattern matching
`Operation not permitted`	Use `sudo` or run as the process owner
Process did not stop	Try `SIGTERM` first, then escalate to `-9` only if needed
Script fails when nothing matches	Handle exit code `1` as a non-match condition

Use these guides for deeper signal and process-management workflows.

Guide	Description
pkill Command in Linux	Full `pkill` guide with examples
kill Command in Linux	Send signals by PID
pgrep Command in Linux	Search processes by name and pattern
ps Command in Linux	Inspect current process list
top Command in Linux	Monitor processes in real time

ln Cheatsheet

hello@linuxize.com (Linuxize) — Tue, 03 Mar 2026 09:30:00 +0100

Basic Syntax

Core ln command forms.

Command	Description
`ln TARGET LINK_NAME`	Create a hard link
`ln -s TARGET LINK_NAME`	Create a symbolic (soft) link
`ln -sf TARGET LINK_NAME`	Create or overwrite a symbolic link
`ln TARGET... DIRECTORY`	Create hard links to multiple targets in a directory
`ln -s TARGET... DIRECTORY`	Create symbolic links to multiple targets in a directory

Symbolic Links

Create and manage soft links that point to a path.

Command	Description
`ln -s /etc/nginx/sites-available/app /etc/nginx/sites-enabled/app`	Enable an Nginx virtual host
`ln -s /usr/bin/python3 /usr/local/bin/python`	Create a `python` alias
`ln -s /opt/myapp /usr/local/bin/myapp`	Link a binary into PATH
`ln -s TARGET .`	Create a symlink to TARGET in the current directory
`ln -sf NEW_TARGET LINK_NAME`	Update an existing symlink to point to a new target

Hard Links

Create additional directory entries pointing to the same inode.

Command	Description
`ln source.txt hardlink.txt`	Create a hard link to a file
`ln file1.txt file2.txt /backup/`	Create hard links to multiple files in a directory
`ln -v source.txt link.txt`	Show each link as it is created

Hard links share the same inode and data. Removing one does not delete the data until all hard links are removed. Hard links cannot span filesystems and cannot be created for directories.

Link Options

Flags for controlling overwrite, backup, and verbosity behavior.

Option	Description
`-s`, `--symbolic`	Create a symbolic link instead of a hard link
`-f`, `--force`	Remove the destination file if it exists before linking
`-b`, `--backup`	Make a backup of each existing destination file
`-i`, `--interactive`	Prompt before removing an existing destination file
`-n`, `--no-dereference`	Treat a symlink to a directory as a normal file
`-v`, `--verbose`	Print the name of each linked file
`-r`, `--relative`	Create symbolic links relative to the link location

Inspect and Verify Links

Check where links point and confirm they are valid.

Command	Description
`ls -l link_name`	Show the link and its target
`ls -la /path/`	List all entries including hidden symlinks
`readlink link_name`	Print the target of a symbolic link
`readlink -f link_name`	Print the fully resolved absolute path
`stat link_name`	Show full metadata including inode and link count
`file link_name`	Identify whether a path is a symbolic link
`find . -type l`	Find all symbolic links under the current directory
`find . -xtype l`	Find broken symbolic links

Troubleshooting

Quick checks for common ln issues.

Issue	Check
`File exists`	Use `-f` to force overwrite, or `-i` to confirm before replacing
`Too many levels of symbolic links`	A circular symlink chain exists; use `readlink -f` to trace the path
`Invalid cross-device link`	Hard links cannot span different filesystems; use a symbolic link instead
Broken symlink (dangling)	The target path no longer exists; update with `ln -sf NEW_TARGET LINK_NAME`
Symlink points to wrong target	Run `readlink link_name` to confirm the current target, then use `ln -sf` to correct it

Use these guides for full workflows and file management patterns.

Guide	Description
ln Command in Linux	Full `ln` tutorial with examples
How to Remove Symbolic Links in Linux	Delete symlinks safely
unlink Command in Linux	Remove a single link entry
ls Command in Linux	List and inspect files and links
chmod Command in Linux	Set permissions on files and links

tee Cheatsheet

hello@linuxize.com (Linuxize) — Sun, 01 Mar 2026 16:20:00 +0100

Basic Syntax

Core tee command forms.

Command	Description
`command \| tee file.txt`	Show output and write to a file
`command \| tee -a file.txt`	Show output and append to a file
`command \| tee file1.txt file2.txt`	Write output to multiple files
`command \| tee`	Pass output through unchanged
`command \| tee /tmp/out.log >/dev/null`	Write to file without terminal output

Common Options

Frequently used flags for tee.

Option	Description
`-a`, `--append`	Append to files instead of overwriting
`-i`, `--ignore-interrupts`	Ignore interrupt signals
`--help`	Show help text
`--version`	Show version information

Logging Command Output

Capture output while still seeing it live.

Command	Description
`ping -c 4 linuxize.com \| tee ping.log`	Save ping output to a log file
`journalctl -u nginx -n 50 \| tee nginx.log`	Save recent service logs
`ls -la \| tee listing.txt`	Save directory listing
`df -h \| tee disk-usage.txt`	Save filesystem usage report
`free -h \| tee memory.txt`	Save memory snapshot

Append Mode

Keep history in log files with -a.

Command	Description
`date \| tee -a run.log`	Append current date to log
`echo "deploy started" \| tee -a deploy.log`	Append status line
`./backup.sh 2>&1 \| tee -a backup.log`	Append stdout and stderr
`tail -n 20 app.log \| tee -a diagnostics.log`	Append recent log excerpt
`curl -I https://linuxize.com \| tee -a headers.log`	Append response headers

Pipelines and Filters

Combine tee with text-processing commands.

Command	Description
`cat app.log \| tee copy.log \| grep ERROR`	Copy stream and filter errors
`ps aux \| tee processes.txt \| grep nginx`	Save process list and filter
`sort users.txt \| tee sorted-users.txt \| uniq`	Save sorted output and deduplicate
`dmesg \| tee dmesg.txt \| tail -n 30`	Save kernel messages and inspect recent lines
`find /etc -maxdepth 1 -type f \| tee etc-files.txt \| wc -l`	Save file list and count lines

Privileged Writes

Write to root-owned files safely.

Command	Description
`echo "127.0.0.1 app.local" \| sudo tee -a /etc/hosts`	Append host mapping as root
`printf "key=value\n" \| sudo tee /etc/myapp.conf >/dev/null`	Overwrite config file as root
`cat config.conf \| sudo tee /etc/myapp/config.conf >/dev/null`	Copy config into protected path
`echo "net.ipv4.ip_forward=1" \| sudo tee -a /etc/sysctl.conf`	Append kernel setting
`sudo sysctl -p \| tee sysctl-apply.log`	Save reload output

Troubleshooting

Quick checks for common tee issues.

Issue	Check
`Permission denied`	Use `sudo tee` for root-owned targets instead of `sudo echo ... > file`
File content replaced unexpectedly	Use `-a` when you need append mode
No output on terminal	Remove `>/dev/null` if you want to see output
Missing errors in logs	Redirect stderr too: `2>&1 \| tee file.log`
Command hangs in pipeline	Check whether the upstream command runs continuously and needs manual stop

Use these guides for deeper command coverage and workflow patterns.

Guide	Description
tee Command in Linux	Full `tee` command tutorial
grep Command in Linux	Filter matching lines
sort Command in Linux	Sort text output
tail Command in Linux	Inspect and follow recent lines
head Command in Linux	Show first lines quickly
journalctl Command in Linux	Query and filter systemd logs
Bash Append to File	Append redirection patterns

gzip Cheatsheet

hello@linuxize.com (Linuxize) — Sun, 01 Mar 2026 12:20:00 +0100

Basic Syntax

Core command forms for gzip and gunzip.

Command	Description
`gzip FILE`	Compress a file and replace it with `FILE.gz`
`gzip -k FILE`	Compress and keep original file
`gzip -d FILE.gz`	Decompress a `.gz` file
`gunzip FILE.gz`	Decompress a `.gz` file
`zcat FILE.gz`	Print decompressed content to stdout

Compression Levels

Control speed versus compression ratio.

Command	Description
`gzip -1 FILE`	Fastest compression, larger output
`gzip -6 FILE`	Default compression level
`gzip -9 FILE`	Maximum compression, slower
`gzip -k -9 FILE`	Max compression while keeping original

Compress Multiple Files

Apply gzip to groups of files.

Command	Description
`gzip *.log`	Compress all matching log files
`gzip -r logs/`	Recursively compress files in a directory
`find . -name '*.txt' -print0 \| xargs -0 gzip`	Compress matching files safely
`for f in *.csv; do gzip -k "$f"; done`	Compress files and keep originals
`gzip -- *.txt`	Compress files, safe for dash-prefixed names

Decompress and Inspect

Restore and verify compressed files.

Command	Description
`gunzip archive.gz`	Decompress and remove `.gz` file
`gzip -dk archive.gz`	Decompress and keep `.gz` file
`gzip -l archive.gz`	Show compressed/uncompressed sizes
`gzip -v FILE`	Show compression ratio and details
`gzip -t archive.gz`	Test integrity without extracting
`zcat archive.gz \| less`	View content without writing files

Streams and Pipelines

Use gzip without intermediate files.

Command	Description
`mysqldump mydb \| gzip > mydb.sql.gz`	Compress command output directly
`gzip -c file.txt > file.txt.gz`	Write compressed output to stdout
`gunzip -c backup.sql.gz > backup.sql`	Decompress to a chosen file
`tar -cf - project/ \| gzip > project.tar.gz`	Create compressed tar stream
`gzip -dc access.log.gz \| grep ERROR`	Search content in compressed logs

Troubleshooting

Quick checks for common gzip issues.

Issue	Check
`gzip: command not found`	Install `gzip` package and verify with `gzip --version`
Original file disappeared after compression	Use `-k` to keep source files
`not in gzip format`	Confirm file type with `file filename` before decompression
Corrupt archive errors	Run `gzip -t file.gz` to validate integrity
Unexpected overwrite behavior	Use `-k` or output redirection with `-c` to control file writes

Use these guides for full workflows and archive handling.

Guide	Description
gzip Command in Linux	Full `gzip` tutorial with examples
gunzip Command in Linux	Decompress `.gz` files in detail
How to Create Tar Gz File	Build compressed tar archives
Tar Command in Linux	Create and extract tar archives
Find Large Files in Linux	Locate files before compression cleanup

cat Cheatsheet

hello@linuxize.com (Linuxize) — Fri, 27 Feb 2026 19:20:00 +0100

Basic Syntax

Core cat command forms.

Command	Description
`cat FILE`	Print a file to standard output
`cat FILE1 FILE2`	Print multiple files in sequence
`cat`	Read from standard input until EOF
`cat -n FILE`	Show all lines with line numbers
`cat -b FILE`	Number only non-empty lines

View File Content

Common read-only usage patterns.

Command	Description
`cat /etc/os-release`	Print distro information file
`cat file.txt`	Show full file content
`cat file1.txt file2.txt`	Show both files in one stream
`cat -A file.txt`	Show tabs/end-of-line/non-printing chars
`cat -s file.txt`	Squeeze repeated blank lines

Line Numbering and Visibility

Inspect structure and hidden characters.

Command	Description
`cat -n file.txt`	Number all lines
`cat -b file.txt`	Number only non-blank lines
`cat -E file.txt`	Show `$` at end of each line
`cat -T file.txt`	Show tab characters as `^I`
`cat -v file.txt`	Show non-printing characters

Combine Files

Create merged outputs from multiple files.

Command	Description
`cat part1 part2 > merged.txt`	Merge files into a new file
`cat header.txt body.txt footer.txt > report.txt`	Build one file from sections
`cat a.txt b.txt c.txt > combined.txt`	Join several text files
`cat file.txt >> archive.txt`	Append one file to another
`cat *.log > all-logs.txt`	Merge matching files (shell glob)

Create and Append Text

Use cat with redirection and here-docs.

Command	Description
`cat > notes.txt`	Create/overwrite a file from terminal input
`cat >> notes.txt`	Append terminal input to a file
`cat <<'EOF' > config.conf`	Write multiline text safely with a here-doc
`cat <<'EOF' >> config.conf`	Append multiline text using a here-doc
`cat > script.sh <<'EOF'`	Create a script file from inline content

Pipelines and Common Combos

Practical command combinations with other tools.

Command	Description
`cat access.log \| grep 500`	Filter matching lines
`cat file.txt \| wc -l`	Count lines
`cat file.txt \| head -n 20`	First 20 lines
`cat file.txt \| tail -n 20`	Last 20 lines
`cat file.txt \| tee copy.txt >/dev/null`	Copy stream to a file

Troubleshooting

Quick checks for common cat usage issues.

Issue	Check
`Permission denied`	Check ownership and file mode with `ls -l`; run with correct user or `sudo` if required
Output is too long	Pipe to `less` (`cat file \| less`) or use `head`/`tail`
Unexpected binary output	Verify file type with `file filename` before printing
File was overwritten accidentally	Use `>>` to append, not `>`; enable shell noclobber if needed
Hidden characters break scripts	Inspect with `cat -A` or `cat -vET`

Use these guides for full file-view and text-processing workflows.

Guide	Description
How to Use the cat Command in Linux	Full `cat` command guide
head Command in Linux	Show the first lines of files
tail Command in Linux	Follow and inspect recent lines
tee Command in Linux	Write output to file and terminal
wc Command in Linux	Count lines, words, and bytes
Create a File in Linux	File creation methods
Bash Append to File	Safe append patterns

sort Cheatsheet

hello@linuxize.com (Linuxize) — Fri, 27 Feb 2026 09:20:00 +0100

Basic Syntax

Core sort command forms.

Command	Description
`sort file.txt`	Sort lines alphabetically (ascending)
`sort -r file.txt`	Sort lines in reverse order
`sort -n file.txt`	Sort numerically
`sort -nr file.txt`	Sort numerically, largest first
`sort file1 file2`	Merge and sort multiple files

Sort by Field

Sort lines by one column or key.

Command	Description
`sort -k2 file.txt`	Sort by second field
`sort -k2,2 file.txt`	Sort using only field 2 as key
`sort -t: -k3,3n /etc/passwd`	Sort by UID field in `/etc/passwd`
`sort -t, -k1,1 data.csv`	Sort CSV by first column
`sort -k3,3 -k1,1 file.txt`	Secondary sort: key 3, then key 1

Numeric and Human Sizes

Handle numbers and size suffixes correctly.

Command	Description
`sort -n numbers.txt`	Numeric sort
`sort -g values.txt`	General numeric sort (floats/scientific notation)
`sort -h sizes.txt`	Sort human-readable sizes (K, M, G)
`du -sh /var/* \| sort -h`	Sort `du` output by size
`sort -V versions.txt`	Natural version sort (`1.9` before `1.10`)

Unique and Check

Detect duplicates and verify sorted input.

Command	Description
`sort -u file.txt`	Sort and remove duplicate lines
`sort file.txt \| uniq`	Equivalent two-step unique output
`sort file.txt \| uniq -c`	Count duplicate occurrences
`sort -c file.txt`	Check if file is sorted
`sort -C file.txt`	Quiet sorted-check (status code only)

In-Place and Output

Safe ways to write sorted results.

Command	Description
`sort file.txt > sorted.txt`	Write output to a new file
`sort -o file.txt file.txt`	Sort in place safely
`sort -o out.txt in.txt`	Write sorted output with `-o`
`sort -T /tmp bigfile.txt`	Use temp directory for large sorts
`LC_ALL=C sort file.txt`	Byte-order sort for predictable locale behavior

Common Pipelines

Practical combinations with other commands.

Command	Description
`grep -Eo '[[:alnum:]_]+' file.txt \| sort \| uniq -c \| sort -rn`	Top repeated words
`cut -d',' -f2 data.csv \| sort`	Sort one CSV column
`sort access.log \| uniq -c \| sort -rn \| head`	Most common log lines
`ps -eo user= \| sort \| uniq -c \| sort -rn`	Process count by user
`find . -type f \| sort`	Sorted file listing

Troubleshooting

Quick checks for common sort issues.

Issue	Check
Numbers sorted as text	Add `-n` (or `-g` for floats)
Size values ordered incorrectly	Use `-h` for human-readable sizes
Unexpected uppercase/lowercase order	Use `-f` or set locale with `LC_ALL=C`
File was emptied after sorting	Do not use `sort file > file`; use `sort -o file file`
Different results across systems	Verify locale and use explicit key options (`-k`)

Use these guides for full sorting and text-processing workflows.

Guide	Description
sort Command in Linux	Full `sort` guide with examples
`uniq`	Remove and count duplicate lines after sorting
head Command in Linux	Show the first lines of output
wc Command in Linux	Count lines, words, and bytes
cut Command in Linux	Extract fields from text
grep Command in Linux	Search and filter matching lines

ps Cheatsheet

hello@linuxize.com (Linuxize) — Thu, 26 Feb 2026 09:10:00 +0100

Basic Syntax

Core ps command forms.

Command	Description
`ps`	Show processes in the current shell
`ps -e`	Show all running processes
`ps -f`	Show full-format output
`ps aux`	BSD-style all-process listing with user and resource info
`ps -ef`	SysV-style all-process listing

List Processes

Common process listing commands.

Command	Description
`ps -e`	List all processes
`ps -ef`	Full process list with PPID and start time
`ps aux`	Detailed list including CPU and memory usage
`ps -u username`	Processes owned by a specific user
`ps -p 1234`	Show one process by PID

Select and Filter

Filter output to specific process groups.

Command	Description
`ps -C nginx`	Match processes by command name
`ps -p 1234,5678`	Show multiple PIDs
`ps -u root -U root`	Show processes by effective and real user
`ps -t pts/0`	Show processes attached to a terminal
`ps -eo pid,ppid,cmd,%mem,%cpu --sort=-%cpu`	Custom output sorted by CPU

Custom Output Columns

Show only the process fields you need.

Command	Description
`ps -eo pid,cmd`	PID and command
`ps -eo user,pid,%cpu,%mem,cmd`	User, PID, CPU, memory, command
`ps -eo pid,lstart,cmd`	PID with full start time
`ps -o pid= -o comm=`	Output without column headers
`ps -p 1234 -o pid,ppid,user,%cpu,%mem,cmd`	Custom fields for one PID

Process Tree and Parent/Child

Inspect process hierarchy.

Command	Description
`ps -ejH`	Hierarchical process view
`ps -axjf`	Forest view (BSD style)
`ps -o pid,ppid,cmd -p 1234`	Parent-child context for one process
`ps -eo pid,ppid,cmd --sort=ppid`	Group processes by parent PID

Useful Patterns

Common real-world combinations.

Command	Description
`ps aux \| grep nginx`	Quick process search (includes grep line)
`ps -C nginx -o pid,cmd`	Cleaner command-name search without grep
`ps -eo pid,%cpu,%mem,cmd --sort=-%mem \| head`	Top memory consumers
`ps -eo pid,%cpu,cmd --sort=-%cpu \| head`	Top CPU consumers
`ps -ef \| grep -v grep \| grep sshd`	Legacy grep pipeline pattern

Troubleshooting

Quick checks for common ps usage issues.

Issue	Check
Command not visible in output	Use `ps -ef` or `ps aux` for full list
Process disappears between checks	It may be short-lived; sample repeatedly or use `watch`
`grep` shows itself	Use `ps -C name` or `pgrep` instead of raw grep
Missing expected process details	Add fields with `-o` (for example `%cpu`, `%mem`, `lstart`)
Need exact process ID for kill	Use `ps -C name -o pid=` or `pgrep name`

Use these guides for full process-management workflows.

Guide	Description
`Ps Command in Linux`	Full `ps` guide with examples
`Kill Command in Linux`	Terminate processes by PID
`Pkill Command in Linux`	Kill processes by name/pattern
`Pgrep Command in Linux`	Find process IDs by name and pattern
`How to Kill a Process in Linux`	Practical process-stop workflow

cp Cheatsheet

hello@linuxize.com (Linuxize) — Wed, 25 Feb 2026 10:35:00 +0100

Basic Syntax

Core command forms for copy operations.

Command	Description
`cp [OPTIONS] SOURCE DEST`	Copy one file to destination
`cp [OPTIONS] SOURCE... DIRECTORY`	Copy multiple sources into a directory
`cp -r [OPTIONS] SOURCE DEST`	Copy directory recursively
`cp -- FILE DEST`	Copy file whose name starts with `-`

Copy Files

Common file copy commands.

Command	Description
`cp file.txt /tmp/`	Copy file to another directory
`cp file.txt newname.txt`	Copy and rename in same directory
`cp file1 file2 /backup/`	Copy multiple files to a directory
`cp *.log /var/log/archive/`	Copy files matching pattern
`cp /src/file.txt /dest/newname.txt`	Copy and rename to another directory

Copy Directories

Copy entire directory trees.

Command	Description
`cp -r dir/ /dest/`	Copy directory recursively
`cp -r dir1 dir2 /dest/`	Copy multiple directories
`cp -r /src/dir /dest/dir-new`	Copy and rename directory
`cp -r dir/. /dest/`	Copy directory contents only (not the directory itself)

Overwrite Behavior

Control what happens when the destination already exists.

Command	Description
`cp -i file.txt /dest/`	Prompt before overwrite
`cp -n file.txt /dest/`	Never overwrite existing file
`cp -f file.txt /dest/`	Force overwrite without prompt
`cp -u file.txt /dest/`	Copy only if source is newer than destination

Preserve Attributes

Keep timestamps, ownership, and permissions when copying.

Command	Description
`cp -p file.txt /dest/`	Preserve mode, ownership, and timestamps
`cp -a dir/ /dest/`	Archive mode — preserve all attributes, copy recursively
`cp --preserve=timestamps file.txt /dest/`	Preserve only timestamps
`cp --preserve=mode file.txt /dest/`	Preserve only permissions

Useful Patterns

Common real-world cp command combinations.

Command	Description
`cp file.txt{,.bak}`	Quick backup via brace expansion
`cp -v file.txt /dest/`	Verbose output
`cp -rv dir/ /dest/`	Verbose recursive copy output
`find . -name '*.conf' -exec cp -t /backup/ {} +`	Copy matched files with `find`
`cp -a /src/. /dest/`	Mirror directory preserving all attributes

Troubleshooting

Quick checks for common copy errors.

Issue	Check
`omitting directory`	Add `-r` to copy directories
`Permission denied`	Check source read permission and destination write permission
`No such file or directory`	Verify source path with `ls -l source`
Destination file overwritten	Use `-i` or `-n` to protect existing files
Attributes not preserved	Use `-a` or `-p` to preserve ownership and timestamps

Note: cp -t in the find example is GNU-specific and may not be available on non-GNU systems.

Use these guides for detailed copy workflows.

Guide	Description
`Linux cp Command: Copy Files and Directories`	Full `cp` guide with examples
`How to Copy Files and Directories in Linux`	Overview of all copy tools
`mv Cheatsheet`	Move and rename files
`rsync Cheatsheet`	Remote and local sync with progress

chown Cheatsheet

hello@linuxize.com (Linuxize) — Tue, 24 Feb 2026 10:30:00 +0100

Basic Syntax

Use these core command forms for chown.

Command	Description
`chown USER FILE`	Change file owner
`chown USER:GROUP FILE`	Change owner and group
`chown :GROUP FILE`	Change group only
`chown USER: FILE`	Change owner and set group to user’s login group
`chown --reference=REF FILE`	Copy owner and group from another file

Common Examples

Common ownership changes for files and directories.

Command	Description
`chown root file.txt`	Set owner to `root`
`chown www-data:www-data /var/www/index.html`	Set owner and group for a web file
`sudo chown $USER:$USER file.txt`	Return ownership to current user
`chown :developers app.log`	Change group only
`chown --reference=source.txt target.txt`	Match ownership of another file

Recursive Changes

Apply ownership updates to full directory trees.

Command	Description
`chown -R USER:GROUP /path`	Recursively change owner and group
`chown -R USER /path`	Recursively change owner only
`chown -R :GROUP /path`	Recursively change group only
`chown -R -h USER:GROUP /path`	Change symlink ownership itself during recursion
`chown -R --from=OLDUSER:OLDGROUP NEWUSER:NEWGROUP /path`	Change only matching current ownership

Symlinks and Traversal

Control how chown treats symbolic links.

Command	Description
`chown USER:GROUP symlink`	Change target by default
`chown -h USER:GROUP symlink`	Change symlink itself (not target)
`chown -R -H USER:GROUP /path`	Follow symlink command-line args to directories
`chown -R -L USER:GROUP /path`	Follow all directory symlinks
`chown -R -P USER:GROUP /path`	Never follow symlinks (default)

Safe Patterns

Use these patterns to avoid ownership mistakes.

Command	Description
`chown --from=root root:root /path/file`	Change only if current owner matches
`find /path -user olduser -exec chown newuser {} +`	Target only files owned by one user
`find /path -group oldgroup -exec chown :newgroup {} +`	Target only one group
`ls -l /path/file`	Verify ownership before and after changes
`id username`	Confirm user and group names exist

Common Errors

Quick checks when ownership changes fail.

Issue	Check
`Operation not permitted`	You need root privileges; run with `sudo`
`invalid user`	Verify user exists with `getent passwd username`
`invalid group`	Verify group exists with `getent group groupname`
Changes did not apply recursively	Confirm `-R` was used
Access still denied after `chown`	Check permission bits with `ls -l` and ACLs

Use these guides for full ownership and permissions workflows.

Guide	Description
`Chown Command in Linux`	Full `chown` guide with examples
`chgrp Command in Linux`	Change file group ownership
`How to Change File Permissions in Linux (chmod command)`	Update permission bits
`Understanding Linux File Permissions`	Ownership and permission model
`How to List Groups in Linux`	Check group membership and IDs

rm Cheatsheet

hello@linuxize.com (Linuxize) — Mon, 23 Feb 2026 09:20:00 +0100

Basic Syntax

Core command forms for file and directory removal.

Command	Description
`rm [OPTIONS] FILE...`	Remove one or more files
`rm -r [OPTIONS] DIRECTORY...`	Remove directories recursively
`rm -- FILE`	Treat argument as filename even if it starts with `-`
`rm -i FILE`	Prompt before each removal

Remove Files

Common file deletion commands.

Command	Description
`rm file.txt`	Remove one file
`rm file1 file2 file3`	Remove multiple files
`rm *.log`	Remove files matching pattern
`rm -- -strange-filename`	Remove file named with leading `-`
`rm -v file.txt`	Remove file with verbose output

Remove Directories

Delete directories and their contents.

Command	Description
`rm -r dir/`	Remove directory recursively
`rm -rf dir/`	Force recursive removal without prompts
`rm -r dir1 dir2`	Remove multiple directories
`rm -r -- */`	Remove all directories in current path

Prompt and Safety Options

Control how aggressively rm deletes files.

Command	Description
`rm -i file.txt`	Prompt before each file removal
`rm -I file1 file2`	Prompt once before deleting many files
`rm --interactive=always file.txt`	Always prompt
`rm --interactive=once *.tmp`	Prompt once
`rm -f file.txt`	Ignore nonexistent files, never prompt

Useful Patterns

Frequent real-world combinations.

Command	Description
`find . -type f -name '*.tmp' -delete`	Remove matching temporary files
`find . -type d -empty -delete`	Remove empty directories
`rm -rf -- build/ dist/`	Remove common build directories
`rm -f -- .bak .old`	Remove backup files quietly

Troubleshooting

Quick checks for common removal errors.

Issue	Check
`Permission denied`	Check ownership and permissions; use `sudo` only when needed
`Is a directory`	Add `-r` to remove directories
`No such file or directory`	Verify path and shell glob expansion
Cannot remove write-protected file	Use `-i` for prompts or `-f` to force
File name starts with `-`	Use `rm -- filename`

Use these references for safer file management workflows.

Guide	Description
`Rm Command in Linux`	Full `rm` guide with examples
`How to Find Files in Linux Using the Command Line`	Find and target files before deleting
`Chmod Command in Linux`	Fix permission errors before removal
`Linux Commands Cheatsheet`	General Linux command quick reference

mv Cheatsheet

hello@linuxize.com (Linuxize) — Sun, 22 Feb 2026 15:15:00 +0100

Basic Syntax

Core command forms for move and rename operations.

Command	Description
`mv [OPTIONS] SOURCE DEST`	Move or rename one file/directory
`mv [OPTIONS] SOURCE... DIRECTORY`	Move multiple sources into destination directory
`mv file.txt newname.txt`	Rename file in same directory
`mv dir1 dir2`	Rename directory

Move Files

Move files between directories.

Command	Description
`mv file.txt /tmp/`	Move one file to another directory
`mv file1 file2 /backup/`	Move multiple files
`mv *.log /var/log/archive/`	Move files matching pattern
`mv /src/file.txt /dest/newname.txt`	Move and rename in one step

Move Directories

Move or rename complete directory trees.

Command	Description
`mv project/ /opt/`	Move directory to another location
`mv olddir newdir`	Rename directory
`mv dir1 dir2 /dest/`	Move multiple directories
`mv /src/dir /dest/dir-new`	Move and rename directory

Overwrite Behavior

Control what happens when destination already exists.

Command	Description
`mv -i file.txt /dest/`	Prompt before overwrite
`mv -n file.txt /dest/`	Never overwrite existing file
`mv -f file.txt /dest/`	Force overwrite without prompt
`mv -u file.txt /dest/`	Move only if source is newer

Backup and Safety

Protect destination files while moving.

Command	Description
`mv -b file.txt /dest/`	Create backup of overwritten destination
`mv --backup=numbered file.txt /dest/`	Numbered backups (`.~1~`, `.~2~`)
`mv -v file.txt /dest/`	Verbose output
`mv -iv file.txt /dest/`	Interactive + verbose

Useful Patterns

Common real-world mv command combinations.

Command	Description
`mv -- *.txt archive/`	Move files when names may start with `-`
`mv "My File.txt" /dest/`	Move file with spaces in name
`find . -maxdepth 1 -name '*.tmp' -exec mv -t /tmp/archive {} +`	Move matched files safely with `find`
`mv /path/file{,.bak}`	Quick rename via brace expansion

Troubleshooting

Quick checks for common move/rename errors.

Issue	Check
`No such file or directory`	Verify source path with `ls -l source`
`Permission denied`	Check destination permissions and ownership
Wrong file overwritten	Use `-i` or `-n` for safer moves
Wildcard misses hidden files	`*` does not match dotfiles by default
Option-like filename fails	Use `--` before source names

Use these guides for detailed move and rename workflows.

Guide	Description
`How to Move Files in Linux with mv Command`	Full mv guide with examples
`How to Rename Files in Linux`	File renaming patterns and tools
`How to Rename Directories in Linux`	Directory rename methods
`Cp Command in Linux: Copy Files and Directories`	Compare copy vs move workflows

ls Cheatsheet

hello@linuxize.com (Linuxize) — Sat, 21 Feb 2026 09:30:00 +0100

Basic Listing

Use these commands for everyday directory listing.

Command	Description
`ls`	List files in current directory
`ls /path/to/dir`	List files in specific directory
`ls -1`	One entry per line
`ls -a`	Include hidden files
`ls -A`	Include hidden files except `.` and `..`

Long Format and Metadata

Show permissions, ownership, size, and timestamps.

Command	Description
`ls -l`	Long listing format
`ls -lh`	Human-readable file sizes
`ls -la`	Long format with hidden files
`ls -n`	Numeric UID and GID
`ls -li`	Show inode numbers

Sorting

Sort files by time, size, extension, or version.

Command	Description
`ls -lt`	Sort by modification time (newest first)
`ls -ltr`	Sort by modification time (oldest first)
`ls -lS`	Sort by file size (largest first)
`ls -lX`	Sort by extension
`ls -lv`	Natural sort for version-like names

Time Display

Control which timestamp is shown.

Command	Description
`ls -lt --time=atime`	Sort/show by access time
`ls -lt --time=ctime`	Sort/show by status change time
`ls -l --time-style=long-iso`	ISO-like date format
`ls -l --full-time`	Full timestamp precision

Directory Views

List directories recursively or show directory entries only.

Command	Description
`ls -la --group-directories-first`	Long listing with directories before files
`ls -d */`	List only directories in current path
`ls -ld /path/to/dir`	Show metadata for directory itself
`ls -R`	Recursive listing
`ls -laR`	Recursive long listing with hidden files

Output Formatting

Adjust visual style and indicators.

Command	Description
`ls -F`	Append indicator (`/`, `*`, `@`) by file type
`ls -p`	Append `/` to directories
`ls -m`	Comma-separated output
`ls -x`	List entries across rows instead of down columns
`ls --color=auto`	Enable colorized output when supported

Filtering with Globs

List files that match shell patterns.

Command	Description
`ls *.log`	List files ending in `.log`
`ls file?.txt`	Match single-character wildcard
`ls [ab]*.conf`	Match names starting with `a` or `b`
`ls -d .[^.]*`	List hidden files (common shell pattern)

Common Patterns

Frequent command combinations.

Command	Description
`ls -lah`	Most common detailed listing
`ls -lhS`	Largest files first with readable sizes
`ls -lat`	Newest files first including hidden entries
`ls -1 \| wc -l`	Count entries in current directory
`ls -l \| grep '^d'`	Show only directories from long listing

Troubleshooting

Quick checks for typical listing issues.

Issue	Check
Hidden files not visible	Add `-a` or `-A`
File sizes are hard to read	Use `-h` with `-l`
Wrong sort order	Confirm flags (`-t`, `-S`, `-X`, `-r`)
No color output	Try `ls --color=auto` and check alias settings
Path looks empty	Verify permissions with `ls -ld /path`

Use these references for deeper file management workflows.

Guide	Description
`How to List Files in Linux Using the ls Command`	Full ls guide with practical examples
`Du Command in Linux`	Check disk usage and file sizes
`Linux Commands Cheatsheet`	General command quick reference

ZIP/UNZIP Cheatsheet

hello@linuxize.com (Linuxize) — Thu, 19 Feb 2026 10:30:00 +0100

Basic Syntax

Common command forms for ZIP operations.

Command	Description
`zip [OPTIONS] archive.zip files`	Create or update ZIP archive
`unzip [OPTIONS] archive.zip`	Extract ZIP archive
`zip -r archive.zip directory/`	Recursively archive a directory
`unzip archive.zip -d /path/`	Extract to a specific directory
`unzip -t archive.zip`	Test archive integrity

Create ZIP Archives

Create archives from files and directories.

Command	Description
`zip archive.zip file1 file2`	Archive multiple files
`zip -r project.zip project/`	Archive directory recursively
`zip -j archive.zip path/to/file`	Archive files without directory paths (flat)
`zip -9 -r backup.zip /etc/`	Maximum compression
`zip -0 -r store.zip media/`	No compression (faster)
`zip -r logs.zip /var/log -x "*.gz"`	Exclude matching files
`zip -q -r archive.zip dir/`	Create archive silently (no output)

Update Existing Archives

Add, refresh, or remove archive entries.

Command	Description
`zip archive.zip newfile.txt`	Add file to existing archive
`zip -r archive.zip newdir/`	Add directory to existing archive
`zip -u archive.zip file.txt`	Update only changed files
`zip -d archive.zip "*.tmp"`	Delete matching entries
`zip -FS archive.zip`	Sync archive with filesystem state

List and Inspect

Check archive contents before extraction.

Command	Description
`unzip -l archive.zip`	List archived files
`unzip -Z -v archive.zip`	Detailed listing (sizes, ratio, methods)
`zipinfo archive.zip`	Display archive metadata
`zipinfo -1 archive.zip`	List filenames only
`unzip -t archive.zip`	Test archive integrity

Extract Archives

Extract all files or selected paths.

Command	Description
`unzip archive.zip`	Extract into current directory
`unzip archive.zip -d /tmp/extract`	Extract to target directory
`unzip archive.zip file.txt`	Extract one file
`unzip archive.zip "dir/*"`	Extract matching path pattern
`unzip -n archive.zip`	Never overwrite existing files
`unzip -o archive.zip`	Overwrite existing files without prompt
`unzip -q archive.zip`	Extract silently (no output)

Password-Protected Archives

Create and extract encrypted ZIP files.

Command	Description
`zip -e secure.zip file.txt`	Create encrypted archive (interactive password)
`zip -er secure-dir.zip secrets/`	Encrypt directory archive
`unzip secure.zip`	Extract encrypted ZIP (prompts for password)
`zipcloak archive.zip`	Add encryption to an existing archive
`zipcloak -d archive.zip`	Remove encryption from archive

Split Archives

Split large ZIP files into smaller chunks.

Command	Description
`zip -r -s 100m backup.zip bigdir/`	Create split archive with 100 MB parts
`zip -s 0 split.zip --out merged.zip`	Recombine split ZIP into one file
`unzip split.zip`	Extract split archive (all parts required)
`zip -s 2g -r media.zip media/`	Create split archive with 2 GB parts

Troubleshooting

Common ZIP/UNZIP problems and checks.

Issue	Check
`unzip: cannot find or open`	Verify path and filename, then run `ls -lh archive.zip`
CRC error during extraction	Run `unzip -t archive.zip` to test integrity
Files overwritten without warning	Use `unzip -n archive.zip` to skip existing files
Wrong file permissions after extract	Check with `ls -l`, then adjust using `chmod`/`chown`
Password prompt fails	Re-enter password carefully; verify archive is encrypted with `zipinfo`

Use these guides for full walkthroughs.

Guide	Description
`How to Zip Files and Directories in Linux`	Detailed ZIP creation examples
`How to Unzip Files in Linux`	Detailed extraction methods
`Tar Cheatsheet`	Tar and compressed archive reference

IP Command Cheatsheet

hello@linuxize.com (Linuxize) — Thu, 19 Feb 2026 08:30:00 +0100

Basic Syntax

Use this structure for most ip operations.

Command	Description
`ip [OPTIONS] OBJECT COMMAND`	General `ip` command syntax
`ip -br a`	Show addresses in brief format
`ip -c a`	Show colorized output
`ip -4 a`	Show only IPv4 addresses
`ip -6 a`	Show only IPv6 addresses

Show Interfaces and Addresses

Inspect links and assigned IP addresses.

Command	Description
`ip link show`	Show all network interfaces
`ip link show dev eth0`	Show one interface
`ip addr show`	Show all IP addresses
`ip addr show dev eth0`	Show addresses on one interface
`ip -br addr`	Brief interface and address overview

Add and Remove IP Addresses

Assign or remove IP addresses on interfaces.

Command	Description
`sudo ip addr add 192.168.1.50/24 dev eth0`	Add IPv4 address
`sudo ip addr del 192.168.1.50/24 dev eth0`	Remove IPv4 address
`sudo ip addr add 2001:db8::50/64 dev eth0`	Add IPv6 address
`sudo ip addr flush dev eth0`	Remove all addresses from interface
`ip addr show dev eth0`	Verify interface addresses

Bring Interfaces Up or Down

Enable, disable, or rename network links.

Command	Description
`sudo ip link set dev eth0 up`	Bring interface up
`sudo ip link set dev eth0 down`	Bring interface down
`sudo ip link set dev eth0 mtu 9000`	Change MTU
`sudo ip link set dev eth0 name lan0`	Rename interface
`ip -br link`	Show link state quickly

Routing Table

Inspect and manage network routes.

Command	Description
`ip route show`	Show IPv4 routing table
`ip -6 route show`	Show IPv6 routing table
`ip route get 8.8.8.8`	Show route used for destination
`sudo ip route add default via 192.168.1.1`	Add default gateway
`sudo ip route del default`	Remove default gateway
`sudo ip route add 10.10.0.0/16 via 192.168.1.254 dev eth0`	Add static route

Neighbor (ARP/NDP) Table

View and manage neighbor cache entries.

Command	Description
`ip neigh show`	Show neighbor table
`ip neigh show dev eth0`	Show neighbors for one interface
`sudo ip neigh flush dev eth0`	Clear neighbor entries on interface
`sudo ip neigh del 192.168.1.10 dev eth0`	Remove a neighbor entry
`ip -s neigh`	Show neighbor statistics

Policy Routing

Work with multiple routing tables and rules.

Command	Description
`ip rule show`	List policy routing rules
`sudo ip rule add from 192.168.10.0/24 table 100`	Route source subnet using table 100
`sudo ip route add default via 10.0.0.1 table 100`	Add default route to custom table
`sudo ip rule del from 192.168.10.0/24 table 100`	Remove policy rule
`ip route show table 100`	Show routes in table 100

Network Namespaces

Inspect or run commands inside network namespaces.

Command	Description
`ip netns list`	List network namespaces
`sudo ip netns add ns1`	Create namespace
`sudo ip netns exec ns1 ip a`	Run `ip a` inside namespace
`sudo ip netns del ns1`	Delete namespace
`ip -n ns1 route`	Show routes in namespace

Troubleshooting

Fast checks for common network issues.

Issue	Check
No IP assigned to interface	`ip addr show dev eth0`
Interface is down	`ip link show dev eth0` then `sudo ip link set dev eth0 up`
Wrong default route	`ip route show` and verify `default via ...`
Cannot reach destination	`ip route get DESTINATION_IP`
Stale ARP/neighbor entry	`sudo ip neigh flush dev eth0`

Use these articles for detailed networking workflows.

Guide	Description
`Linux ip Command with Examples`	Complete `ip` command guide
`How to Find Your IP Address in Linux`	Public and private IP lookup methods
`Traceroute Command in Linux`	Path and hop diagnostics
`UFW Cheatsheet`	Firewall rules quick reference

Cheatsheets on Linuxize

npm Cheatsheet

Project Setup #

Install Dependencies #

Clean Installs #

Versions and Updates #

Remove and Clean #

Scripts and Execution #

Inspect Packages #

Configuration #

Security and Audit #

Related Guides #

Podman Cheatsheet

Container Lifecycle #

Container Inspection #

Logs #

Images and Builds #

Exec and Copy #

Volumes #

Networks #

Pods #

Rootless and systemd #

Compose #

System and Cleanup #

Registry and Login #

Docker Compatibility #

dpkg Cheatsheet

Install and Remove #

Query Installed Packages #

Package Files #

Inspect deb Files #

Extract deb Files #

Package Selections #

Repair and Configure #

Related Guides #

reboot Cheatsheet

Immediate Reboot #

systemctl Options #

Schedule with shutdown -r #

Cancel and Status #

ripgrep Cheatsheet

Basic Search #

File Type Filters #

Glob Filters #

Case and Literal Search #

Counts and File Lists #

Context Output #

Patterns and Regex #

Hidden and Ignored Files #

Replacement Preview #

Troubleshooting #

Common Options #

Related Guides #

ss Cheatsheet

Basic Syntax #

Filter by Protocol #

Listening Ports #

Connection State Filters #

Address and Port Filters #

Process and Statistics #

netstat to ss Translation #

Troubleshooting #

Related Guides #

nmcli Cheatsheet

Basic Syntax #

General Status #

Devices #

Connection Profiles #

Wi-Fi #

Static IPv4 #

DHCP and DNS #

Add Profiles #

Scripting Output #

Monitor and Reload #

Troubleshooting #

Related Guides #

fdisk Cheatsheet

Basic Usage #

List Disks #

Interactive Commands #

Project Setup

Install Dependencies

Clean Installs

Versions and Updates

Remove and Clean

Scripts and Execution

Inspect Packages

Configuration

Security and Audit

Related Guides

Container Lifecycle

Container Inspection

Logs

Images and Builds

Exec and Copy

Volumes

Networks

Pods

Rootless and systemd

Compose

System and Cleanup

Registry and Login

Docker Compatibility

Install and Remove

Query Installed Packages

Package Files

Inspect deb Files

Extract deb Files

Package Selections

Repair and Configure

Related Guides

Immediate Reboot

systemctl Options

Schedule with shutdown -r

Cancel and Status

Basic Search

File Type Filters

Glob Filters

Case and Literal Search

Counts and File Lists

Context Output

Patterns and Regex

Hidden and Ignored Files

Replacement Preview

Troubleshooting

Common Options

Related Guides

Basic Syntax

Filter by Protocol

Listening Ports

Connection State Filters

Address and Port Filters

Process and Statistics

netstat to ss Translation

Troubleshooting

Related Guides

Basic Syntax

General Status

Devices

Connection Profiles

Wi-Fi

Static IPv4

DHCP and DNS

Add Profiles

Scripting Output

Monitor and Reload

Troubleshooting

Related Guides

Basic Usage

List Disks

Interactive Commands

Partition Tables

Create Partitions

Partition Types

Review and Save

Format and Mount

Safety Checks

Related Tools

Connect and Authenticate

Local and Remote Paths