uniq command in linux with example

In this tutorial, I use uniq command to report or omit repeated lines in Linux. Now, let’s go uniq command in Linux for example.

What does uniq command mean?

uniq – report or omit repeated lines

Syntax

uniq [OPTION]... [INPUT [OUTPUT]]

In the man page, the describes it

• uniq – report or omit repeated lines.
• man uniq – More details information about uniq command.

uniq command in Linux with example

I have created a file uniq_command.txt as below

[vagrant@DevopsRoles ~]$ cat uniq_command.txt 
 HuuPV, My website DevopsRoles.com and HuuPhan.com.SN:199x.
 Devops Roles.
 Devops Roles.
 Devops Roles.
 Devops Roles.
 Hello world :)

Remove duplicate lines with uniq command.

[vagrant@DevopsRoles ~]$ uniq uniq_command.txt 
 HuuPV, My website DevopsRoles.com and HuuPhan.com.SN:199x.
 Devops Roles.
 Hello world :)

The number of times a line was repeated

[vagrant@DevopsRoles ~]$ uniq -c uniq_command.txt 
       1 HuuPV, My website DevopsRoles.com and HuuPhan.com.SN:199x.
       4 Devops Roles.
       1 
       1 Hello world :)

It only prints the repeated lines.

[vagrant@DevopsRoles ~]$ uniq -d uniq_command.txt 
 Devops Roles.

Prints all repeated duplicate line

[vagrant@DevopsRoles ~]$ uniq -D uniq_command.txt 
 Devops Roles.
 Devops Roles.
 Devops Roles.
 Devops Roles.

How to not print the duplicate lines. Only the unique lines.

[vagrant@DevopsRoles ~]$ uniq -u uniq_command.txt 
 HuuPV, My website DevopsRoles.com and HuuPhan.com.SN:199x.
 Hello world :)

Conclusion

uniq command is a simple command in Linux. It is used to report or omit repeated lines. Thank you for reading the DevopsRoles page!