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Text Processing

uniq

Removes or reports adjacent duplicate lines.

uniq works on neighboring duplicate lines, so it is commonly paired with sort.

Syntax
uniq [options] [input [output]]

Arguments explained

  • -c counts duplicate runs.
  • -d prints only repeated lines.
  • -u prints only unique lines.

Common examples

Count repeated lines
sort access.log | uniq -c | sort -nr | head

Counts and ranks repeated log lines.

Remove adjacent duplicates
uniq names.txt

Prints names with neighboring duplicates collapsed.

uniq Command
FieldDetails
Commanduniq
CategoryText Processing
Primary useRemoves or reports adjacent duplicate lines.
Syntaxuniq [options] [input [output]]

Related articles

sort

Sorts lines of text.

comm

Compares two sorted files line by line.

wc

Counts lines, words, bytes, or characters.