Name
uniq – report or omit repeated lines
Synopsis
uniq [OPTION]… [INPUT [OUTPUT]]
Description
Discard all but one of successive identical lines from INPUT (or standard input), writing to OUTPUT (or standard output).
Mandatory arguments to long options are mandatory for short options too.
- -c, –count
- prefix lines by the number of occurrences
- -d, –repeated
- only print duplicate lines
- -D, –all-repeated[=delimit-method]
- print all duplicate lines delimit-method={none(default),prepend,separate} Delimiting is done with blank lines.
- -f, –skip-fields=N
- avoid comparing the first N fields
- -i, –ignore-case
- ignore differences in case when comparing
- -s, –skip-chars=N
- avoid comparing the first N characters
- -u, –unique
- only print unique lines
- -z, –zero-terminated
- end lines with 0 byte, not newline
- -w, –check-chars=N
- compare no more than N characters in lines
- –help
- display this help and exit
- –version
- output version information and exit
A field is a run of whitespace, then non-whitespace characters. Fields are skipped before chars.
Note: ’uniq’ does not detect repeated lines unless they are adjacent. You may want to sort the input first, or use ‘sort -u’ without ‘uniq’.
Author
Written by Richard Stallman and David MacKenzie.
Reporting Bugs
Report bugs to <bug-coreutils@gnu.org>.
Copyright
Copyright © 2008 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html >
This is free software:you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.
See Also
The full documentation for uniq is maintained as a Texinfo manual. If the info and uniq programs are properly installed at your site, the command
- info uniq
should give you access to the complete manual.