Linux Commands Cheat Sheet

📁 Navigation

Command	What It Does	Example
`pwd`	Print working directory (where you are)	/Users/jeff/Documents
`ls`	List files and directories	Shows files in current directory
`ls -la`	List all files (including hidden) with details	Shows permissions, owner, size, date
`cd directory`	Change to a directory	cd Documents
`cd ..`	Go up one level (parent directory)	From /docs to /
`cd ~`	Go to home directory	/Users/jeff
`cd -`	Go back to previous directory	Toggles between last two locations
`tree`	Show folders as a tree	Helpful for seeing structure fast

📄 File Operations

🏠 Create

`mkdir name`	Create a directory
`touch file`	Create empty file
`cp file new`	Copy file
`cp -r dir newdir`	Copy directory recursively

🔄 Move & Rename

`mv file dir/`	Move file to directory
`mv old new`	Rename file/directory
`mv -i file dir/`	Move with confirmation

🗑️ Delete (Careful!)

`rm file`	Delete file (no undo!)
`rm -r dir`	Delete directory + contents
`rm -i file`	Delete with confirmation
`rmdir empty-folder`	Delete an empty directory

👁️ View Files

`cat file`	Display entire file
`less file`	View with pagination (q to quit)
`head file`	Show first 10 lines
`tail file`	Show last 10 lines
`tail -f file`	Watch file in real-time
`nano file`	Open a simple text editor
`wc -l file`	Count the lines in a file

🔍 Search & Find

📂 Find Files

`find . -name "*.txt"`	Find all .txt files
`find . -name "report"`	Find files with "report" in name
`find . -type d`	Find all directories
`find . -size +1M`	Find files larger than 1MB

🔎 Search Inside Files

`grep "word" file`	Search for text in file
`grep -r "word" dir/`	Search recursively in directory
`grep -i "word" file`	Case-insensitive search
`grep -n "word" file`	Show line numbers

📦 Installing Software

Command	What It Does
`sudo apt update`	Refresh the package list before installing things
`sudo apt upgrade`	Install available updates
`sudo apt install package`	Install a program
`sudo apt remove package`	Uninstall a program
`sudo apt autoremove`	Clean up packages you no longer need
`apt search package`	Search for a package by name
`apt show package`	See details about a package

⚙️ System Commands

Command	What It Does
`date`	Show current date and time
`cal`	Show calendar
`whoami`	Show current username
`uname -a`	Show system information
`df -h`	Show disk space (human readable)
`du -sh */`	Show directory sizes
`free -h`	Show memory and swap usage
`top`	Live view of running processes
`htop`	Interactive process viewer
`ps aux`	List running processes
`uptime`	Show how long the machine has been running
`lsb_release -a`	Show Ubuntu version details
`history`	Show command history
`man command`	Show manual for command
`command --help`	Quick help for command

🌐 Networking

🔌 Connection Basics

`ip a`	Show IP addresses and network interfaces
`ping host`	Test whether you can reach a host
`curl url`	Fetch a web page or API response
`wget url`	Download a file from the web

🖥️ Remote Access

`ssh user@host`	Connect to another machine
`scp file user@host:/path`	Copy a file to another machine
`which program`	Show where a command lives
`nslookup domain`	Look up a domain's IP address

🔐 File Permissions

Understanding ls -la Output

-rwxr-xr-- 1 user group 1234 Jan 15 10:30 script.sh

Position 1: File Type

- = Regular file
d = Directory
l = Link

Positions 2-10: Permissions

r = Read
w = Write
x = Execute
- = No permission

Permission Groups

2-4: Owner
5-7: Group
8-10: Others

Command	Description
`chmod +x file`	Make file executable
`chmod 755 file`	Owner: rwx, Group: r-x, Others: r-x
`chmod 644 file`	Owner: rw-, Group: r--, Others: r--
`chown user file`	Change file owner

⌨️ Keyboard Shortcuts & Handy Patterns

⌨️ Shortcuts

`Tab`	Auto-complete a command or filename
`Ctrl + C`	Stop the current command
`Ctrl + L`	Clear the screen
`Ctrl + R`	Search command history
`↑ / ↓`	Scroll through previous commands

🔗 Pipes & Redirects

`cmd \| less`	Scroll through long output
`cmd \| grep word`	Filter output for a word
`cmd > file`	Save output to a file
`cmd >> file`	Append output to a file
`cmd1 && cmd2`	Run the second command only if the first succeeds

Quick Reference Card

Navigation

pwd — Where am I?
ls — List files
cd dir — Change directory
cd .. — Go up
cd ~ — Home

Files

mkdir — Create folder
touch — Create file
cp — Copy
mv — Move/Rename
rm — Delete

View

cat — Show file
less — Page through
head — First 10 lines
tail — Last 10 lines
grep — Search

🎯 Need Help?

Stuck on a command? Not sure what to do next? The fastest way to get unstuck is to ask Claude. Just describe what you're trying to do or paste the error.

Example 1: Paste an error

"I got this error: [paste error message] What does it mean?"

Example 2: Screenshot

"This isn't working as expected [attach screenshot]"

Example 3: Plain language

"I need to find all files modified in the last 24 hours"

No shame in asking. Claude can see your screen, understand context, and give you the exact command you need.