uniq.md

uniq

output one copy of each line in input.txt uniq input.txt

count occurrences of lines uniq -c count.txt

output only lines that are duplicated uniq -d repeats.txt

output only the lines that are not repeated in unique.txt uniq -u unique.txt

output unique lines ignoring case uniq -i case.txt

Basic Usage

Output a single copy of each unique line in a file: uniq

uniq

Output the unique lines from the given input or file.
Since it does not detect repeated lines unless they are adjacent, we need to sort them first.

• Display each line once:

  sort file | uniq

• Display only unique lines:

  sort file | uniq -u

• Display only duplicate lines:

  sort file | uniq -d

• Display number of occurrences of each line along with that line:

  sort file | uniq -c

• Display number of occurrences of each line, sorted by the most frequent:

  sort file | uniq -c | sort -nr

To show all lines without duplication:

(sort -u and uniq have the same effect.)

sort | uniq

To show not duplicated lines:

sort | uniq -u

To show duplicated lines only:

sort | uniq -d

To count all lines:

sort | uniq -c

To count not duplicated lines:

sort | uniq -uc

To count only duplicated lines:

sort | uniq -dc