Linux uniq command - removes duplicate lines from the output file

Linux uniq command: removes duplicate lines from the output file

Linux uniq command Function Description

Use the uniq command to remove duplicate rows of data within a file from the output file, leaving only a unique sample of each record.

Linux uniq command Syntax

uniq [option] [file]

The meaning of each option in the command is shown in the table:

Option	Description
-c	Show the output with the number of times this line appears in the file at the beginning of each line
-d	Output only duplicate rows
-D	Show all duplicate rows
-u	Show only unduplicated lines in the file
-s K	The first K characters are skipped when comparing, K is a number
-w K	The content after the Kth character of each line is not cross-referenced, K is a number
-f K	The first K columns are skipped when comparing, K is the number
-i	Case insensitive when comparing

Linux uniq command Demo

View the contents of duplicate rows of data in the file file3

[root@rhel ～]# cat file3
aaa
aaa
bbb
// View the contents of the file file3
[root@rhel ～]# uniq -d file3
aaa
// The content of the duplicate row of data in the file3 file is aaa

View the content of unduplicated rows of data in the file file3

The content of the unduplicated row of data in the /var/apidemos.com.txt file is:

uniq -u /var/apidemos.com.txt

Output:

Show the number of consecutive occurrences of each line in the file3 file

[root@rhel ～]# uniq -c file3
      2 aaa
      1 bbb

Show all duplicate lines of file3 file, each duplicate line is displayed

[root@rhel ～]# uniq -D file3
aaa
aaa