`uniq` command

Remove or count repeated adjacent lines.

Text processing
Package coreutils
4 options · 4 examples

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Syntax
Common options
Examples
Tips
Related commands

Syntax

uniq [options] [input [output]]

Provided by the coreutils package. Run man uniq for the full manual.

Common options

Option	What it does
`-c`	Prefix each line with its count
`-d`	Only print duplicated lines
`-u`	Only print unique lines
`-i`	Ignore case

Examples

Remove duplicates (sort first)
```
sort list.txt | uniq
```
Count occurrences
```
sort list.txt | uniq -c
```

Most common lines first

sort access.log | uniq -c | sort -rn | head

Only lines that repeat
```
sort list.txt | uniq -d
```

Tips

uniq only compares neighbouring lines, so sort the input first.

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