uniq 命令

常用示例

说明

uniq filters adjacent matching lines from input, writing unique lines to output. It only compares consecutive lines, so input typically needs to be sorted first. Commonly used with sort in a pipeline: sort file | uniq removes all duplicates. Adding -c shows frequency counts, useful for analyzing log files or finding common patterns. The -d option shows only lines that appear more than once, while -u shows only lines appearing exactly once. These are mutually exclusive perspectives on the data. Field and character skipping options allow ignoring prefixes (like timestamps or line numbers) when comparing for uniqueness.

参数

-c, --count

Prefix lines with occurrence count

-d, --repeated

Only print duplicate lines, one per group

-D

Print all duplicate lines

-u, --unique

Only print unique lines (occurring once)

-i, --ignore-case

Ignore case when comparing

-f _N_, --skip-fields=_N_

Skip first N fields when comparing

-s _N_, --skip-chars=_N_

Skip first N characters when comparing

-w _N_, --check-chars=_N_

Compare only first N characters

-z, --zero-terminated

Line delimiter is NUL, not newline