Linux Commands
Command references for core Linux tools, syntax, examples, and practical one-liners.
passwd Command in Linux: Change User Passwords
Change your own, another user's, or the root password in Linux with the passwd command. Covers password expiry with chage, forcing a change at next login, and account locking.
tree Command in Linux: Display Directory Structure
The tree command lists directories recursively as an indented tree. This guide covers installation, depth limits, filtering, sizes, and saving the output.
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.
nohup Command in Linux: Background Jobs and Output
nohup keeps commands running after logout. The 'appending output to nohup.out' message is not an error. This guide covers background jobs, 2>&1 redirection, and stopping processes.
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.
strace Command in Linux: Trace System Calls
Use the strace command to trace system calls and signals on Linux, debug why a program fails, find missing files, and measure where a process spends its time.
How to Manage Node.js Processes with PM2
How to install PM2, run and manage Node.js processes with clustering, zero-downtime reloads, log rotation, and systemd integration that survives reboots.
htop Command in Linux: How to Monitor and Manage Processes
Monitor Linux processes in real time with htop: read CPU and memory meters, sort and filter the process list, and kill or renice processes from one screen.
smartctl Command in Linux: Check Disk Health with SMART
Use smartctl in Linux to check SMART health, read disk attributes, run self-tests, troubleshoot USB enclosures, and monitor NVMe wear.
ffmpeg Command in Linux: Convert, Compress, and Extract Media
Practical ffmpeg examples for converting between formats, compressing video with CRF, extracting audio, trimming clips, resizing video, and batch processing files on Linux.
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.
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.
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.
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.
