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Learn Linux commands by actually typing them.

A real shell in your browser, a course that checks every command you run, and examples you will actually use.

Start the course Browse commands

A live sandbox with its own files. Press Enter, then try help.

Command guides: 52
Interactive lessons: 60
Printable cheat sheets: 15
Fixes & recipes: 43

Command reference

Syntax, an options table, real-world examples and a terminal to practice in, for every command.

ls List the contents of a directory, with options for hidden files, long format, sorting and more. cd Move between directories: absolute and relative paths, home shortcut, and jumping back. grep Find lines matching a pattern in files or piped input: the workhorse of text search. find Locate files anywhere in a directory tree by name, type, size, date, and act on them. chmod Change file permissions with numeric (755, 644) and symbolic (u+x) modes: clearly explained. tar Create and extract archives: tar.gz, tar.bz2, with the flag combinations finally explained. ssh Log into remote machines, run remote commands, use keys instead of passwords, and tunnel ports. ps See what is running, find a process ID, and combine with grep to hunt down a program. kill Terminate processes politely or forcibly, and understand what -9 really does. curl Download files, test APIs, send POST requests with JSON, and inspect headers. sed Stream-edit text: substitute, delete lines, and edit files in place with -i. awk Pull columns out of any output, filter rows, and compute sums: the shell's spreadsheet.

All 52 command guides

In-depth guides

Beginners: start here

The 15 commands that cover 90% of daily use, in learning order.

$ pwd
$ ls -la
$ cd ~/projects

Permissions explained

rwxr-xr-x, 755 vs 644 and chown: the model behind the numbers.

Pipes & redirection

stdin, stdout, stderr and composing commands into pipelines.

Bash scripting

Variables, conditions, loops and exit codes. Your first automation.

Directory structure

What /etc, /var, /usr and /proc are for, and where to look when things break.

Cheat sheets worth printing

One A4 page per topic: the three commands you will use daily, the full sheet, and the mistakes to avoid.

Navigation Files & directories Viewing files Search Pipes & redirection Text processing Permissions & ownership Processes Disk & memory Networking Remote & transfer Archives & compression System & services Shell & environment Keyboard shortcuts

Everything on one page

Just need to get something done?

Task-shaped guides that open with the command and explain it afterwards.

All how-to guides

Something broken right now?

One page per error: what it means, the likely causes, and the fix for each.

All error messages

Which tool should I use?

Side-by-side comparisons of tools people confuse, each ending in a verdict.

rsync vs scp curl vs wget sed vs awk symbolic link vs hard link grep vs ripgrep (rg)tar.gz vs zip

Why learn the Linux command line?

The terminal is the common interface behind almost everything technical: servers, containers, CI pipelines, cloud instances, embedded devices and your own development machine. Graphical tools come and go, but ls, grep and chmod have worked the same way for decades and will keep working for decades more. A few hours of deliberate practice with the core commands pays off for an entire career.

The catch is that reading about commands doesn't build the muscle memory. Typing them does. That's the whole idea behind this site: every page gives you a safe sandbox where mistakes cost nothing, so you can experiment until each command feels automatic.