ls: List files and folders
ls -l: List with details like size and permissions
ls -a: List all files including hidden ones
cd folder: Change into a folder
cd ..: Go up one folder
cd ~ or cd: Go to your home folder
pwd: Print the current working directory
mkdir name: Make a new folder
rmdir name: Remove an empty folder
touch file: Create an empty file or update its timestamp
cp a b: Copy a file
cp -r a b: Copy a folder and its contents
mv a b: Move or rename a file
rm file: Delete a file (no undo)
rm -r folder: Delete a folder and contents (dangerous)
cat file: Show a file's contents
less file: View a file one page at a time
head file: Show the first lines of a file
tail file: Show the last lines of a file
tail -f file: Follow a file as new lines are added
echo text: Print text
grep pattern file: Search for text in a file
grep -r pattern .: Search recursively through folders
find . -name 'x': Find files by name
wc -l file: Count lines in a file
sort file: Sort lines
uniq: Remove repeated adjacent lines
diff a b: Show differences between two files
chmod: Change file permissions
chmod +x file: Make a file executable
chown: Change the owner of a file
sudo: Run a command with administrator privileges
su: Switch user
whoami: Show the current user name
man command: Show the manual for a command
--help: Show brief help for a command
history: Show previous commands
clear: Clear the terminal screen
Ctrl+C: Stop the running command
Ctrl+D: End input or log out
Ctrl+L: Clear the screen
Up arrow: Recall the previous command
Tab key: Auto-complete a name
ps: Show running processes
top or htop: Show live process and resource usage
kill PID: Stop a process by its ID
df -h: Show disk space
du -sh folder: Show a folder's size
free -h: Show memory usage
uname -a: Show system information
date: Show the date and time
ping host: Test network reachability
curl url: Transfer data from a URL
wget url: Download a file
ssh user@host: Log in to a remote machine securely
scp: Copy files securely between machines
tar -czf out.tar.gz folder: Create a compressed archive
tar -xzf file.tar.gz: Extract an archive
zip and unzip: Compress and extract zip files
apt install pkg: Install a package on Debian or Ubuntu
brew install pkg: Install a package on macOS with Homebrew
| (pipe): Send the output of one command into another
> (redirect): Write output to a file, replacing it
>> (append): Add output to the end of a file
< (input redirect): Use a file as input
&& (and): Run the next command only if the first succeeds
& (background): Run a command in the background
* (wildcard): Matches any characters in filenames
~ (tilde): Your home directory
. (dot): The current directory
.. (dot dot): The parent directory
/ (root): The top of the file system
Absolute path: A path starting from /
Relative path: A path starting from the current folder
Environment variable: A named value available to programs, like PATH
PATH: A list of folders where the shell looks for commands
export VAR=value: Set an environment variable
Shell: A program that reads your commands
bash: A popular shell
Kernel: The core of an operating system
Linux creator: Linus Torvalds, first released in 1991
Tux: The penguin mascot of Linux
Permissions rwx: Read, write and execute
Hidden file: A file whose name begins with a dot
nano: A simple text editor in the terminal
vim: A powerful text editor, famous for being hard to exit (:q)

Free flashcards from Peabody at peabody.kids/flashcards/tech-linux-commands