UNIQ(1) UNIQ(1) NAME uniq - report repeated lines in a file SYNOPSIS uniq [ -udc [ +-num ] ] [ file ] DESCRIPTION Uniq copies the input file, or the standard input, to the standard output comparing adjacent lines. In the normal case, the second and succeeding copies of repeated lines are removed. Repeated lines must be adjacent in order to be found. -u Print unique lines. -d Print (one copy of) duplicated lines. -c Prefix a repetition count and a tab to each output line. Implies -u and -d. -num The first num fields together with any blanks before each are ignored. A field is defined as a string of non-space, non-tab characters separated by tabs and spaces from its neighbors. +num The first num characters are ignored. Fields are skipped before characters. EXAMPLES cut -d: -f3 /etc/passwd | sort | uniq -d Print duplicated userids from the password file, passwd(5). Cut picks out the userid (the third colon- delimited field) and sort brings repetitions together. SEE ALSO sort(1), comm(1) BUGS Field-selection and comparison should be compatible with sort(1).