Practice Bash online: 10 shell-scripting exercises and a playground

In order, each one introducing a single new idea. Press Run to check your answer; hints open one at a time.

1. 1Trail Signpostecho prints one line, and double quotes keep spacing exactly as typed
2. 2Lost and FoundVariables: name=value with no spaces, $name to use it, and single quotes stop expansion
3. 3Moving-Day Boxes$((...)) does whole-number arithmetic, and printf formats columns but never adds a newline
4. 4Rainwater Tank Gaugeif runs a command and checks its exit status; [ ] compares numbers with -lt/-gt and needs spaces around its brackets
5. 5Photo Rename Planfor loops over a word list, and ${name} braces mark where a variable name ends
6. 6Downloads Tidy-Upcase matches one value against glob patterns, each branch ending in ;;
7. 7Bakery Oven TimesFunctions take $1 $2 arguments, print their result, and are captured with $(...)
8. 8Cabin Guest Book> creates a file, >> appends to it, and while read ... done < file reads it line by line
9. 9Birdwatching TallyPipes chain sort, uniq -c, grep -c and wc -l into a tally
10. 10Library Overdue ReportIFS=, read splits a comma-separated line into fields for that one read

Questions people ask

Is this a real terminal?

No, and it says so on purpose: it is a simulated bash environment (just-bash) that understands real bash syntax and a wide set of everyday commands, running entirely inside your browser tab with an in-memory filesystem. There is no real operating system underneath, no network access, and no way to reach anything outside the sandbox.

Which commands actually work?

Variables, arithmetic, if/case, for/while loops, functions, pipes and redirects, and coreutils like echo, cat, grep, sed, awk, cut, sort, uniq, wc, head and tail. Network tools (curl, wget), compression (gzip, tar) and anything needing a real OS are not available, and the exercises are written around that honestly.

Can I use read to take input?

Yes. Whatever you type into the input box beside the editor is what read receives, one line at a time, exactly as it would from a terminal.

What comes after these exercises?

Beyond the 10 exercises, the Linux commands reference covers the wider command set with real examples, and the git commands reference does the same for everyday Git.