Name
uniq
Synopsis
uniq [options] [file1 [file2]]
Description
Remove duplicate adjacent lines from sorted file1, sending one copy of each line to file2 (or to standard output). Often used as a filter. Specify only one of -d or -u. See also comm and sort.
Options
- - n, -f n, --skip-fields= n
Ignore first n fields of a line. Fields are separated by spaces or by tabs.
- + n, -s n, --skip-chars= n
Ignore first n characters of a field.
- -c, --count
Print each line once, prefixing number of instances.
- -d, --repeated
Print duplicate lines once but no unique lines.
- -i, --ignore-case
Ignore case differences when checking for duplicates.
- -u, --unique
Print only unique lines (no copy of duplicate entries is kept).
- -w n, --check-chars= n
Compare only first n characters per line (beginning after skipped fields and characters).
- --help
Print a help message and then exit.
- --version
Print version information and then exit.
Examples
Send one copy of each line from list to output file list.new:
uniq list list.new
Show which names appear more than once:
sort names | uniq -d
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