Basic Command Reference

To master Linux, you need to get comfortable with the command line. Here is a curated list of essential commands every DevOps engineer should know.

1. Directory Operations

ls: List files and directories in the current folder.
cd: Change directory (e.g., cd /var/log).
pwd: Print working directory (shows where you are).
mkdir: Create a new directory.
rmdir: Remove an empty directory.

2. File Operations

touch: Create a new empty file.
cp: Copy files or directories.
mv: Move or rename files or directories.
rm: Remove files (use -r for directories).
cat: Display the content of a file.

3. Help & Manuals

man: Display the manual for a command (e.g., man ls).
--help: A common flag to see quick help (e.g., mkdir --help).

Command Quick Reference

Command	Usage Example	Result
`ls -la`	`ls -la`	List all files including hidden ones with details.
`cd ..`	`cd ..`	Move up one directory level.
`mkdir docs`	`mkdir docs`	Create a folder named "docs".
`touch app.js`	`touch app.js`	Create an empty file named "app.js".
`cp file.txt /tmp`	`cp file.txt /tmp`	Copy a file to the `/tmp` folder.
`mv old.txt new.txt`	`mv old.txt new.txt`	Rename a file.
`rm -rf folder`	`rm -rf folder`	CAUTION: Recursively delete a folder and its content.

[!WARNING] Use rm -rf with Care The rm -rf / command will attempt to delete everything on your system. Always double-check your path before running a recursive delete!

File System Hierarchy File Ops & Navigation