Table of Contents


uniq - report or omit repeated lines




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

-w, --check-chars=N
compare no more than N characters in lines

--help display this help and exit

output version information and exit

A field is a run of whitespace, then non-whitespace characters. Fields are skipped before chars.


Written by Richard Stallman and David MacKenzie.

Reporting Bugs

Report bugs to <>.


Copyright (C) 2006 Free Software Foundation, Inc. This is free software. You may redistribute copies of it under the terms of the GNU General Public License <>. 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.

Table of Contents

Privacy Policy