10 Hidden Linux Commands Every Sysadmin Should Know

As Linux users, we often rely on the commonly used commands ls , grep , awk , sed and find to complete the work. But Linux has a large number of lesser-known commands that can save time, automate tasks and simplify workflows.

This article will explore some underrated but powerful Linux commands that deserve more attention.

1. rename – efficient batch rename files

The rename command is the savior when you need to rename multiple files at once. Without using a loop containing mv , rename allows you to easily apply complex renaming patterns.

Change all .txt files to .log .

 rename 's/\.txt$/\.log/' *.txt

Convert filename to lowercase.

 rename 'y/AZ/az/' *

Add a prefix to all .jpg files.

 rename 's/^/photo_/' *.jpg

The rename command is much faster than using mv in a loop and avoids potential filename conflicts.

2. pv – Monitor data transmission progress

Do you want to know how quickly your data is transferred between files or devices? pv (Pipe Viewer) command helps by displaying progress bars, estimating time, and transfer rates.

Monitor file copy progress.

 pv bigfile.iso > /mnt/usb/bigfile.iso

Monitor the progress of compressed backups.

 tar cf - /home | pv | gzip > backup.tar.gz

This is very useful when working with large files, as you can see real-time progress without having to wait blindly.

3. timeout – Automatically terminate command after setting time

Sometimes the command runs longer than expected and you want it to stop automatically after a specific period of time, you can use the timeout command.

Stop the command after 10 seconds.

 timeout 10s ping google.com

Stop the process after 1 hour.

 timeout 1h rsync -av /source/ /destination/

This is very useful in scripts and prevents commands from hanging indefinitely.

4. shuf – Randomize input lines or select random entries

Need to mess up the lines in the file or select a random item? shuf is a simple and powerful command for randomizing tasks.

Chaos lines in the file.

 shuf file.txt

Select a line from the file.

 shuf -n 1 file.txt

Generate a random password (12 characters).

 shuf -zer -n12 {A..Z} {a..z} {0..9} | tr -d '\0'

The shuf command is ideal for random sampling, testing and generating random data.

5. comm – Line to line comparison of two sorted files

When working with lists or logs, comm allows you to compare two sorted files and find common or unique rows.

Compare the two user lists.

 comm file1.txt file2.txt

Show only public rows.

 comm -12 file1.txt file2.txt

comm command can be used for log analysis, user management, and comparison configuration.

6. tac – reverse the order of lines in a file

You know cat , but have you tried tac ? It displays the contents of the file in reverse order, which is a simple and effective trick.

View log files in reverse order.

 tac /var/log/syslog

Reverse the contents of the file and save it.

 tac file.txt > reversed.txt

This is very convenient for quickly reading the latest log entries without using tail -r .

7. nl – Add line number to the file

Need to add line number to the file? nl can do this immediately without modifying the original file.

Number each line of the file.

 nl file.txt

Skip empty lines when numbering.

 nl -ba file.txt

This is very useful when dealing with code snippets, debugging, or formatting logs.

8. yes – Automatic answer tips

Tired of pressing "y" repeatedly to confirm? The yes command automatically enters a response for the prompt.

Automatically confirm the installation of the software package.

 yes | apt install package-name

Test CPU performance by generating infinite output.

 yes > /dev/null

careful! If used improperly, yes may overload your system.

9. watch – Repeat command

Want to monitor the output of commands in real time? watch runs the command at fixed time intervals and refreshes the output.

Monitor available disk space every 2 seconds.

 watch -n 2 df -h

Track changes in the directory.

 watch -d ls -l

Check the system running time every 5 seconds.

 watch -n 5 uptime

This is useful for real-time monitoring of system statistics, log files, or process status.

10. expr – Perform mathematical calculations in shell

Need to perform fast arithmetic operations in shell scripts? expr allows you to add, subtract, multiply and divide.

Basic arithmetic operations.

 expr 10 5
expr 10 \* 5 # Multiply with backslash

Find the remainder of division.

 expr 20 % 3

This is very useful for fast calculations in scripts without using Python or calculator.

Summarize

These little-known Linux commands can simplify tasks, increase efficiency and save time. Whether you are managing files, monitoring processes, or automating tasks, mastering these commands will make you a more powerful Linux user.

Which commands do you find most useful? Please let us know in the comments! ?

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