Linux Shell script programming-uniq command

Uniq

The uniq command can remove duplicate rows from sorted files. Therefore, uniq is often used with sort. That is to say, to make uniq work, all repeated rows must be adjacent.

Uniq syntax

[Root @ WWW ~] # Uniq [-ICU] Option and parameter:-I: Ignore case-insensitive characters;-C: Count-u: show only unique rows

 

The content of testfile is as follows:

Cat testfilehelloworldfriendhelloworldhello

 

Directly Delete unordered files. No rows are deleted.

# Uniq testfile helloworldfriendhelloworldhello

 

Sort files. deduplication is used by default.

# Cat words | sort | uniqfriendhelloworld

 

Duplicate rows are deleted after sorting, and the number of repeated rows is output at the beginning of the row.

# Sort testfile | uniq-C1 friend3 hello2 world

 

Only duplicate rows are displayed, and the number of repeated rows is displayed at the beginning of the row.

# Sort testfile | uniq-DC3 hello2 world

 

Only show non-repeated rows

Sort testfile | uniq-ufriend