easy

The Shell & Filesystem

Navigate directories and work with files using pwd, ls, cd, cat, mkdir, and touch.

The shell is a text interface to your computer: you type a command, it runs, and it prints the result. Bash is the most common one. Everything starts with moving around the filesystem — a tree of directories (folders) and files.

This is a real (simulated) shell running in your browser. Type commands, or click an example. Start with ls and cat readme.txt.

cs shell — type "help" to see commands.

learner@cs:~$

A simulated shell — supports pipes ( | ) and redirection ( > , >> ). Use ↑/↓ for history.

Where am I, and what’s here

pwd — print working directory: where you currently are.
ls — list the contents of a directory. ls -l shows one per line; ls data lists another directory.
cd <dir> — change directory. Special targets: .. (up one level), ~ (home), / (root). Try cd data, then pwd, then cd ...

Paths are either absolute (start at /, e.g. /home/learner) or relative to where you are (e.g. data/fruits.txt).

Reading and making files

cat <file> — print a file’s contents. Try cat data/fruits.txt.
mkdir <name> — make a new directory.
touch <name> — create an empty file (or update its timestamp).
mv / cp / rm — move, copy, remove. (rm -r removes a directory.)

Everything you create lives until you press reset.

Takeaways

The shell is a read-eval-print loop: type a command, see its output.
The filesystem is a tree; pwd, ls, and cd are how you move through it.
Paths are absolute (from /) or relative (from your current directory).