Powerful Linux Commands
- 3 minsRarely Used but Powerful Linux Commands (with Practical Examples)
If you’re comfortable with basic Linux commands and want to push your command-line skills further, this article introduces 10 underused commands that offer real utility. These aren’t just fun to know—they’re practical, powerful, and might just become part of your daily toolkit.
1. ^foo^bar – Quickly Fix a Mistyped Command
Rather than retyping a long command with a small typo, use this history substitution trick to fix and re-run it.
echo Hello foo
^foo^bar
Output:
Hello foo
Hello bar
Note: This only works in Bash with command history enabled. If it doesn’t work, make sure you’re using Bash and not another shell like Zsh or Fish.
2. > file.txt – Instantly Empty a File
A lightning-fast way to clear the contents of any file without opening it.
> logfile.txt
3. at – Schedule a One-Time Task
The at command lets you schedule tasks to run once at a given time. However, if you see:
-bash: at: command not found
You need to install it:
sudo apt install at # Debian/Ubuntu
sudo systemctl enable --now atd # Start the 'at' daemon
Usage:
at now + 2 minutes
at> echo "Backup started" >> /tmp/backup.log
at> <Press Ctrl+D here>
Note: Pressing Ctrl+C while inside at> cancels the job. Always finish by pressing Ctrl+D on a new empty line to submit it
4. du -h --max-depth=1 – Directory Disk Usage Summary
Get a summary of how much space each folder in the current directory uses.
du -h --max-depth=1
Sample Output:
4.0K ./scripts
20M ./downloads
1.2G ./videos
5. expr – Basic Math and String Operations
Use it for quick arithmetic or string manipulation directly in the shell.
expr 9 \* 7
expr length "Linux"
Output:
63
5
6. yes – Repeated Output Generator
Useful for automatically feeding responses to scripts or testing performance.
yes "Proceed with operation"
Output (truncated):
Proceed with operation
Proceed with operation
...
Press Ctrl+C to stop it.
7. factor – Prime Factorization
Quickly find the prime factors of any number.
factor 84
Output:
84: 2 2 3 7
8. ping -i 60 -a – Custom Interval & Audible Ping
Ping every N seconds with optional audible sound on each reply.
ping -i 3 -a 8.8.8.8
Output:
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_seq=1 ttl=119 time=4.04 ms
64 bytes from 8.8.8.8: icmp_seq=2 ttl=119 time=6.34 ms
64 bytes from 8.8.8.8: icmp_seq=3 ttl=119 time=7.42 ms
Tip: The -a option plays a sound, but some environments (like WSL or headless servers) may not have a working speaker or bell. Use echo -e "\a" to test the bell.
9. tac – Reverse File Contents
Display file contents from bottom to top, line by line—very handy for logs.
tac /var/log/syslog
Final Thoughts
Some of these commands may not be installed by default, but they’re well worth having. After installing missing packages like at , you’ll unlock additional tools to automate and streamline your Linux tasks.
Thanks for reading!
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Guneycan Sanli
Guneycan Sanli
A person who like learning, music, travelling and sports.