Linux Commands
Command references for core Linux tools, syntax, examples, and practical one-liners.
less Command in Linux: Navigate and Search Files
The less command displays file contents one page at a time, with full keyboard navigation, search, and multi-file support. This guide covers the most useful options and commands.
Nginx Commands You Should Know
Reference for the most-used Nginx commands on Linux: start, stop, restart, reload, test config, dump config, check version, and read logs with systemd.
ufw Command in Linux: Uncomplicated Firewall Reference
Reference for the ufw command on Linux, with examples for enabling the firewall, allowing and denying traffic, deleting rules, and managing application profiles.
who Command in Bash: List Logged-In Users
The who command lists currently logged-in users, along with their terminal, login time, and remote host. Use it to see active sessions, system boot time, and the current runlevel.
How to Check the Kernel Version in Linux
Three quick ways to find the Linux kernel version from the command line: uname, hostnamectl, and /proc/version.
tmux Command in Linux: Sessions, Windows, and Panes
The tmux command lets you run persistent terminal sessions with multiple windows and panes. This guide covers creating and managing sessions, splitting panes, copy mode, and configuration.
curl Command in Linux: Usage and Examples
The curl command transfers data to and from servers using HTTP, HTTPS, FTP, and other protocols. This guide covers downloads, headers, POST requests, verbose debugging, proxies, and API usage.
passwd Command in Linux: Change User Passwords
Use the passwd command to change your own or another user's password in Linux. Covers root password changes, password expiry with chage, and account locking.
file Command in Linux: Determine File Types
Identify file types from the command line using the Linux file command. Covers basic usage, MIME types, compressed files, symlinks, and the magic database.
Chattr Command in Linux (File Attributes)
How to use chattr and lsattr to set and view file attributes in Linux, including immutable files, append-only logs, and recursive protection.
tail Command in Linux: View the End of Files and Follow Logs
Practical examples of the tail command for viewing the end of files, following logs in real time, and combining tail with grep and other tools.
find Command in Linux: Search Files and Directories
The find command searches for files and directories by name, type, size, date, permissions, and more. This guide covers practical examples including wildcards, exec actions, and combining find with grep.
mkdir Command in Linux: Create Directories
The mkdir command creates directories in Linux from the command line. This guide covers creating single and multiple directories, nested paths with -p, setting permissions, and brace expansion.
env Command in Linux: Show and Set Environment Variables
The env command prints environment variables and runs programs with a modified environment. This guide covers env syntax, running commands with custom variables, clean environments, and portable shebangs.
htop Command in Linux: Monitor Processes Interactively
htop is an interactive process viewer for Linux that shows CPU, memory, and swap usage in real time. This guide covers sorting, filtering, tree view, killing processes, and customizing the display.
nohup Command in Linux: Run Commands After Logout
The nohup command keeps a process running after you log out or close the terminal. This guide covers syntax, background execution, output redirection, and how to manage nohup processes.
nmap Command in Linux with Practical Examples
Use the nmap command in Linux to discover hosts, scan ports, detect services, and understand common scan options such as -sn, -Pn, and -sV.
lsof Command in Linux: List Open Files and Network Connections
The lsof command lists every open file, socket, and network connection on a Linux system. This guide covers how to find what is using a port, trace open files by process or user, and recover disk space from deleted but held-open files.
How to Check for Listening Ports in Linux: Find Open and Used Ports
Use ss, netstat, or lsof to list all listening ports in Linux, identify which process is using a specific port, and filter results by protocol or port number.
How to Unzip Files in Linux
A practical guide to the unzip command: extract ZIP files to a specific directory, handle password-protected archives, list archive contents, and use common flags like -o, -n, -d, and -j.
