Linux Commands
Command references for core Linux tools, syntax, examples, and practical one-liners.
du Command in Linux: Check Disk Usage
The du command reports disk space used by files and directories. This guide covers human-readable output, summary totals, depth limiting, sorting by size, and practical examples.
Linux Wildcards and Globbing Explained
How shell wildcards and globbing work in Linux: the *, ?, and [...] patterns, brace expansion, why globbing is not regex, and how to control it with quoting.
git diff Command: Compare Changes Between Commits and Branches
Use git diff to compare your working directory, staged files, commits, and branches, with practical examples of the options you will use most.
last Command in Linux: Check Login History
Use the last command in Linux to check login history, filter sessions by user or date, and audit system access. Also covers lastb for failed logins and lastlog for per-user login records.
How to Check Listening Ports in Linux: ss, netstat, lsof
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
Extract ZIP archives in Linux with the unzip command: unzip to a folder, handle password-protected and multiple archives, list or test contents, and exclude files.
Hard Links vs Symbolic Links in Linux
Understand the difference between hard links and symbolic links in Linux: how inodes work, when each type breaks, and which one to use for a given task.
date Command in Linux: Format, Timezone, and Epoch
Format dates, convert timezones, and work with Unix timestamps using the Linux date command, with copy-paste examples for the terminal and shell scripts.
Check Linux Version: Find Your Distribution and Kernel Release
Check your Linux version from the terminal with /etc/os-release, hostnamectl, lsb_release, and uname. See when each command is useful.
shutdown Command in Linux: Power Off, Reboot, and Schedule
How to use the shutdown command in Linux to power off, halt, or reboot the system immediately or at a scheduled time, with examples of all common options.
How to Check if a Command Exists in Bash
Check whether a command exists in Bash with command -v, capture its path, validate several dependencies, and compare type, hash, and which.
setuid, setgid, and the Sticky Bit Explained
Understand the setuid, setgid, and sticky bit special permissions in Linux: what each one does on files and directories, how to set them, and the security risks.
How to Rename Files and Directories in Linux
Rename files and directories in Linux using mv for single renames and rename for batch filename changes, including extension changes, case conversion, and safe previews.
modprobe Command in Linux: Load and Manage Kernel Modules
Manage Linux kernel modules with modprobe: load, unload, blacklist, and configure module parameters. Includes syntax, practical examples, and troubleshooting.
curl vs wget: Differences and When to Use Each
Compare curl vs wget defaults, protocols, redirects, recursive downloads, API requests, and resume options to choose the right command for each task.
/etc/passwd in Linux: File Format and Fields Explained
The cat /etc/passwd command displays local Linux accounts. This guide explains its seven fields and when to use getent passwd instead.
at Command in Linux: Schedule One-Time Tasks
The at command schedules one-time tasks to run at a specific time in Linux. This guide covers syntax, time formats, batch jobs, listing and removing jobs, and user restrictions.
Bash Subshells: Isolate Variables and Directory Changes
Bash subshells run commands in an isolated shell environment. This guide explains parentheses, variable scope, directory changes, command substitution, pipelines, and exit codes.
hostnamectl Command in Linux: Set and Query Hostname
Use hostnamectl to view and change the Linux hostname. Covers static, transient, and pretty names, system metadata, remote hosts, and common errors.
host Command in Linux: DNS Lookup
The host command is a simple DNS lookup tool. This guide covers forward and reverse lookups, querying specific record types, using a chosen name server, and reading the output.
