Cheat sheet

The commands from the practice terminal, grouped by what you’re trying to do. Print it; it fits on one page.

Where am I?

pwd: Print working directory: the full path of the folder you're in.
whoami: Prints the name of the user you're logged in as.
hostname: Prints the name of this computer.
id: Shows your user number, your main group, and every group you belong to.

ls: Lists what's in the folder. Folders and files look the same here; try ls -l to tell them apart.
ls -a: -a shows hidden files too. Anything starting with a dot is hidden, and . and .. mean "this folder" and "the one above".
ls -l: -l is the long format: permissions, owner, size in bytes, date changed, name. A d at the start means it's a folder.
ls -la: Long format plus hidden files. This is the one most people type without thinking.
ls -lh: -h turns sizes into K and M instead of bytes. Folders still show 4.0K; that's the folder entry, not what's inside.
ls -R: -R goes into every folder below this one and lists each.

cat notes.txt: cat prints a file's whole contents to the screen. Fine for short files.
head -n 2 notes.txt: head prints the first lines of a file. -n 2 means two lines.
tail -n 2 todo.txt: tail prints the last lines. People use tail -f to watch a log file grow.
wc -l notes.txt: wc counts. -l counts lines only.
grep buy todo.txt: grep prints the lines that contain your word.
grep -i LINUX notes.txt: -i ignores upper and lower case.
sort todo.txt: sort prints the lines in alphabetical order. The file itself doesn't change.

cd docs: cd changes folder. cd .. goes up one, cd on its own goes home.
cd ..: Goes up one folder.
mkdir projects: Makes a folder. No output means it worked. Type ls to see it.
touch new.txt: Creates an empty file, or updates the date on one that exists. Type ls to see it.
cp notes.txt notes-copy.txt: Copies a file. The original stays. Type ls to see both.
mv todo.txt chores.txt: mv moves or renames. Here it renamed the file. Type ls.
rm todo.txt: Deleted. There's no trash can in a terminal; on a real machine that file is gone. Type ls to check.

echo $HOME: $HOME is a variable that holds your home folder. echo shows its value.
du -sh photos: Disk usage. -s gives one total, -h makes it readable. Disk space is counted in 4K blocks, so it's bigger than the files.
find . -name "*.txt": find searches this folder and everything under it. The quotes stop bash from expanding *.txt itself.
./hello.sh: ./ means "the file right here". It runs because ls -l shows x (execute) in its permissions.

Output checked against GNU bash 5.2.37 and coreutils 9.7 on November 10, 2026.