Tab Completion & Command History
Work faster in the shell. Learn tab completion to auto-finish paths and commands, and history to recall, search, and re-run previous commands.
Tab Completion & Command History is a free DevOps Bootcamp lesson on CoddyKit — lesson 4 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the DevOps Bootcamp learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
Working Faster in the Shell
Typing every command in full is slow and error-prone. The shell hands you two big productivity wins: Tab completion and command history.
Tab Completion Basics
Start typing a command or filename and press Tab - the shell finishes it for you when there's only one match, as shown.
cd Doc<Tab> # becomes: cd Documents/Multiple Matches
When several names match, the first Tab does nothing. Press Tab twice to list all candidates, then type one more letter to disambiguate.
ls Down<Tab><Tab>
Downloads/ Downstream/Completing Commands
Tab completes command names too, not just files. Type a prefix and double-Tab to see every command that starts with it.
gi<Tab><Tab>
git gitk ...Viewing History
The history command prints your recently run commands, each with a number you can reuse - as shown below.
history
501 cd /var/log
502 ls -l
503 grep error syslogRepeating with !!
!! reruns your last command. It's perfect with sudo when you forgot it: sudo !! re-runs the previous line as root.
apt update # permission denied
sudo !! # runs: sudo apt updateRunning by Number
Run any past command by its number with !n - for example !502 reruns command 502 from your history.
!502 # reruns the command numbered 502Recalling by Prefix
!prefix reruns the most recent command starting with that text - !grep repeats your last grep.
!grep # reruns the last grep commandArrow Keys
Press the Up and Down arrows to step through previous commands one by one, then edit and Enter to run.
Searching History
Press Ctrl+R for reverse search: start typing and the shell finds the latest matching command; press Ctrl+R again to go further back.
(reverse-i-search): tar
tar -czf backup.tgz logs/Where History Lives
History persists across sessions in a file (often ~/.bash_history). The HISTSIZE variable sets how many commands are kept.
Quick Check
Test your shell skills.
Recap
Recap: work faster with Tab completion (auto-finish, double-Tab to list) and history (history, !!, !n, !prefix, arrows, Ctrl+R).
Frequently asked questions
Is the “Tab Completion & Command History” lesson free?
Yes — the full text of “Tab Completion & Command History” is free to read here on the web, and the DevOps Bootcamp course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the DevOps Bootcamp course, upgrade to CoddyKit PRO.
What will I learn in “Tab Completion & Command History”?
Work faster in the shell. Learn tab completion to auto-finish paths and commands, and history to recall, search, and re-run previous commands. You practise DevOps Bootcamp with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start DevOps Bootcamp?
No prior experience is required. DevOps Bootcamp on CoddyKit is structured for beginners through advanced learners; this is — lesson 4 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “Tab Completion & Command History” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this DevOps Bootcamp lesson?
Yes. Every DevOps Bootcamp lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Introduction to Linux & Terminal
- Navigating the Filesystem (cd, ls, pwd)
- File Management Basics (mkdir, cp, mv, rm)
- Tab Completion & Command History