🐧 Linux Command Handbook

A practical, in-depth Linux command reference — built one command at a time, with real-world examples, the edge cases documentation usually skips, and interview-ready explanations.

Browse commands · What's inside

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This isn't a copy-paste cheat sheet. Every finished page covers what a command actually is, how it works internally, its full syntax, dozens of real-world examples, the edge cases that trip people up, and the kind of questions you'd actually be asked about it in an interview.

🚧 Project status

Completed

⭐ Star or watch this repo to follow new additions, and open an issue to suggest or request a command.

Progress: 50 / 50 commands completed — 100%

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Category	Progress	Status
📁 Files	6 / 6	✅ Complete
🔎 Search	2 / 2	✅ Complete
👤 User Management	3 / 3	✅ Complete
📝 Text Processing	9 / 9	✅ Complete
🧭 Navigation	4 / 4	✅ Complete
💽 Disk	4 / 4	✅ Complete
📦 Archives	2 / 2	✅ Complete
🌐 Networking	6 / 6	✅ Complete
🔐 Permissions	3 / 3	✅ Complete
⚙️ Processes	5 / 5	✅ Complete
🛠️ System	6 / 6	✅ Complete

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📖 What every command page covers

Each command lives in its own folder — commands/<category>/<command>/ — and follows the same four-file format:

File	Purpose
README.md	The complete reference — what it is, how it works internally, full syntax, all options, related commands
examples.md	Real-world, copy-pasteable usage examples
edge-cases.md	Gotchas, quirks, and situations that don't behave the way you'd expect
interview-questions.md	Common interview questions about the command, each with a full answer

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✅ Completed guides

🧭 Navigation — 4 / 4

Command	Description
cd	Change the current directory
ls	List directory contents
pwd	Print the working directory
man	Display manual pages

🔎 Search — 2 / 2

Command	Description
grep	Search text using patterns
find	Search for files in a directory hierarchy

📝 Text Processing — 9 / 9

Command	Description
cat	Concatenate and display file contents
less / more	Page through file contents
sed	Stream text editor
awk	Pattern scanning and text-processing language
sort	Sort lines of text
wc	Count lines, words, and bytes in a stream
diff	Compare file changes
tee	Duplicate command output
pipe	Connect command outputs together

💽 Disk — 4 / 4

Command	Description
df	Report filesystem disk space usage
du	Estimate disk usage of files/directories
lsblk	List block devices
mount	Mount filesystems

📦 Archives — 2 / 2

Command	Description
tar	Archive and compress files
zip / unzip	Compress and extract files

👤 User Management — 3 / 3

Command	Description
useradd	Create a new user account
passwd	Change a user's password
who / w	Show who is logged in

🔐 Permissions — 3 / 3

Command	Description
chmod	Change file permissions
chown	Change file ownership
sudo	Run a command as superuser

⚙️ Processes — 5 / 5

Command	Description
ps	Snapshot of running processes
top	Live, continuously refreshing process monitor
htop	Interactive, colorized process monitor
kill	Send signals to a process
systemctl	Control systemd services

🌐 Networking — 6 / 6

Command	Description
ping	Test host reachability
curl	Transfer data via URLs
wget	Reliably download files
ssh	Secure remote shell
scp	Securely copy files over SSH
netstat	Show network connections and listening ports

🛠️ System — 6 / 6

Command	Description
uname	Print system information
uptime	Show how long the system has been running
env	Display or modify the environment
history	Display command history
alias	Create command shortcuts
cron / crontab	Automated background scheduling

📁 Files — 5 / 6

Command	Description
mkdir	Create new directories
touch	Creates or updates timestamps
rm	Deletes files permanently
cp	Copies files/directories
mv	Renames or relocates files
ln	Links files together

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🗂️ Repository structure

linux-command-handbook/
├── README.md
├── LICENSE
└── commands/
    ├── navigation/
    ├── search/
    ├── text-processing/
    ├── disk/
    ├── archives/
    ├── user/
    ├── permissions/
    ├── processes/
    ├── networking/
    ├── system/
    └── files/
        └── <command>/
            ├── README.md
            ├── examples.md
            ├── edge-cases.md
            └── interview-questions.md

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🎯 Goals

• Learn Linux commands through practical, real-world examples
• Understand the edge cases that documentation usually skips
• Build a reference solid enough for daily use
• Prepare for technical interviews with command-specific Q&A

📜 License

Licensed under CC BY 4.0 — see LICENSE. You're free to share and adapt this content, even commercially, as long as you give appropriate credit.