This documentation is no longer being maintained and may be inaccurate
or incomplete. The Texinfo documentation is now the authoritative source.
This manual page
documents the GNU version of
uniq .
uniq
prints the unique lines in a sorted file, discarding all but one of a
run of matching lines. It can optionally show only lines that appear
exactly once, or lines that appear more than once.
uniq
requires sorted input because it compares only consecutive lines.
If the output file is not specified,
uniq
writes to the standard output. If the input file is not specified, it
reads from the standard input.
-u, --unique
-d, --repeated
Only print duplicate lines.
-c, --count
Print the number of times each line occurred along with the line.
-number, -f, --skip-fields=number
In this option, number is an integer representing the number of
fields to skip over before checking for uniqueness. The first
number fields, along with any blanks found before number
fields is reached, are skipped over and not counted. Fields are
defined as a strings of non-space, non-tab characters, that are
separated from each other by spaces and tabs.
+number, -s, --skip-chars=number
In this option, number is an integer representing the number of
characters to skip over before checking for uniqueness. The first
number characters, along with any blanks found before
number characters is reached, are skipped over and not counted.
If you use both the field and character skipping options, fields are
skipped over first.
-w, --check-chars=number
Specify the number of characters to compare in the lines, after
skipping any specified fields and characters. Normally the entire
rest of the lines are compared.
--help
Print a usage message and exit with a status code indicating success.
--version
Print version information on standard output then exit.