Linux Commands Reference | LLM CLI Training

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Navigation

Moving around the filesystem

Command	What it does	Example
`pwd`	Print current directory	`pwd` → `/home/user`
`ls`	List directory contents	`ls`
`ls -la`	List all files (including hidden) with details	`ls -la`
`cd folder`	Change into a directory	`cd projects`
`cd ..`	Go up one directory	`cd ..`
`cd ~`	Go to home directory	`cd ~`
`cd -`	Go to previous directory	`cd -`

Files & Folders

Creating, copying, moving, deleting

Command	What it does	Example
`mkdir name`	Create a directory	`mkdir my-project`
`mkdir -p a/b/c`	Create nested directories	`mkdir -p src/components/ui`
`touch file`	Create an empty file	`touch index.html`
`cp src dest`	Copy a file	`cp file.txt backup.txt`
`cp -r src dest`	Copy a folder recursively	`cp -r project project-backup`
`mv src dest`	Move or rename	`mv old.txt new.txt`
`rm file`	Delete a file (permanent!)	`rm temp.txt`
`rm -r folder`	Delete a folder recursively	`rm -r old-project`

Reading & Searching

Viewing file contents and finding things

Command	What it does	Example
`cat file`	Print file contents	`cat README.md`
`head file`	Show first 10 lines	`head -20 log.txt`
`tail file`	Show last 10 lines	`tail -f server.log`
`less file`	Scroll through a file (q to quit)	`less long-file.txt`
`grep pattern file`	Search for text in a file	`grep "error" log.txt`
`grep -r pattern dir`	Search recursively in directory	`grep -r "TODO" src/`
`find dir -name pattern`	Find files by name	`find . -name "*.js"`

System Info

Learning about your environment

Command	What it does	Example
`whoami`	Print your username	`whoami` → `user`
`which command`	Show where a command lives	`which node` → `/usr/bin/node`
`echo text`	Print text to screen	`echo "hello"`
`date`	Show current date/time	`date`
`clear`	Clear the terminal screen	`clear`
`history`	Show command history	`history`

Package Managers

Installing software (you'll need these for CLI tools)

Command	What it does	Platform
`npm install -g package`	Install a Node.js package globally	All (needs Node.js)
`npx command`	Run a package without installing	All (needs Node.js)
`brew install package`	Install via Homebrew	macOS / Linux
`apt install package`	Install via APT	Ubuntu / Debian
`winget install package`	Install via Windows Package Manager	Windows

Permissions & Sudo

Running commands with elevated privileges

Command	What it does	Example
`sudo command`	Run as administrator	`sudo npm install -g claude`
`chmod +x file`	Make a file executable	`chmod +x script.sh`
`chown user file`	Change file ownership	`chown user:group file`

ℹYou don't need all of these

The commands from Module 3 (pwd, ls, cd, mkdir, touch, cat, cp, mv, rm) cover 90% of what you’ll do. The rest of this cheat sheet is here for when you need it — which usually means when an AI tool suggests a command and you want to understand what it does.