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UNIQ(1) User Commands UNIQ(1)

NAME

uniq - report or omit repeated lines

SYNOPSIS

uniq [OPTION]... [INPUT [OUTPUT]]

DESCRIPTION

Filter adjacent matching lines from INPUT (or standard input), writing to OUTPUT (or standard output).

With no options, matching lines are merged to the first occurrence.

Mandatory arguments to long options are mandatory for short options too.

prefix lines by the number of occurrences
only print duplicate lines, one for each group
print all duplicate lines groups can be delimited with an empty line METHOD={none(default),prepend,separate}
avoid comparing the first N fields
show all items, separating groups with an empty line METHOD={separate(default),prepend,append,both}
ignore differences in case when comparing
avoid comparing the first N characters
only print unique lines
end lines with 0 byte, not newline
compare no more than N characters in lines
display this help and exit
output version information and exit

A field is a run of blanks (usually spaces and/or TABs), then non-blank 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'. Also, comparisons honor the rules specified by 'LC_COLLATE'.

GNU coreutils online help: <http://www.gnu.org/software/coreutils/> Report uniq translation bugs to <http://translationproject.org/team/>

AUTHOR

Written by Richard M. Stallman and David MacKenzie.

COPYRIGHT

Copyright © 2013 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

comm(1), join(1), sort(1)

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 coreutils 'uniq invocation'

should give you access to the complete manual.

November 2020 GNU coreutils 8.22