uniq(1) [osx man page]
UNIQ(1) BSD General Commands Manual UNIQ(1) NAME
uniq -- report or filter out repeated lines in a file SYNOPSIS
uniq [-c | -d | -u] [-i] [-f num] [-s chars] [input_file [output_file]] DESCRIPTION
The uniq utility reads the specified input_file comparing adjacent lines, and writes a copy of each unique input line to the output_file. If input_file is a single dash ('-') or absent, the standard input is read. If output_file is absent, standard output is used for output. The second and succeeding copies of identical adjacent input lines are not written. Repeated lines in the input will not be detected if they are not adjacent, so it may be necessary to sort the files first. The following options are available: -c Precede each output line with the count of the number of times the line occurred in the input, followed by a single space. -d Only output lines that are repeated in the input. -f num Ignore the first num fields in each input line when doing comparisons. A field is a string of non-blank characters separated from adjacent fields by blanks. Field numbers are one based, i.e., the first field is field one. -s chars Ignore the first chars characters in each input line when doing comparisons. If specified in conjunction with the -f option, the first chars characters after the first num fields will be ignored. Character numbers are one based, i.e., the first character is character one. -u Only output lines that are not repeated in the input. -i Case insensitive comparison of lines. ENVIRONMENT
The LANG, LC_ALL, LC_COLLATE and LC_CTYPE environment variables affect the execution of uniq as described in environ(7). EXIT STATUS
The uniq utility exits 0 on success, and >0 if an error occurs. COMPATIBILITY
The historic +number and -number options have been deprecated but are still supported in this implementation. SEE ALSO
sort(1) STANDARDS
The uniq utility conforms to IEEE Std 1003.1-2001 (``POSIX.1'') as amended by Cor. 1-2002. HISTORY
A uniq command appeared in Version 3 AT&T UNIX. BSD
July 3, 2004 BSD
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uniq(1) General Commands Manual uniq(1) NAME
uniq - report repeated lines in a file SYNOPSIS
fields] chars] [input_file [output_file]] DESCRIPTION
reads the input text file input_file, comparing adjacent lines, and copies the result to output_file. If input_file is not specified, the standard input and standard output are used. If input_file is specified, but output_file is not, results are printed to standard output. input_file and output_file must not be the same file. Line-Comparison Options recognizes the following options when comparing adjacent lines: Print those lines that are repeated in the original file. Print copy only of each repeated line in the input file. Generate an output report in default style except that each line is preceded by a count of the number of times it occurred. If this option is specified, the and options are ignored if either or both are also present. If none of the options or are present, prints the results of the union of the and options, producing a copy of the original input file with the second and succeeding copies of any repeated lines removed. (Note that repeated lines must be adjacent in order to be found -- see sort(1)). Field-Skip Options Two options are provided for skipping an initial portion of each line when making comparisons: Ignore the first fields fields, together with any blanks before each. fields is a positive decimal integer. A field is defined as a string of non-space, non-tab characters separated by tabs and/or spaces from its neighbors. Ignore the first chars characters. chars is a positive decimal integer. Each line in the input is assumed to be terminated with a new line character for purposes of comparison. Fields are skipped before characters. EXTERNAL INFLUENCES
Environment Variables must be equal to the value it had when the input files were sorted. determines the interpretation of text within files as single- and/or multi-byte characters, and defines a space character when the or option is used. determines the language in which messages are displayed. If or is not specified in the environment or is set to the empty string, the value of is used as a default for each unspecified or empty variable. If is not specified or is set to the empty string, a default of "C" (see lang(5)) is used instead of If any internationalization variable contains an invalid setting, behaves as if all internationalization variables are set to "C". See environ(5). International Code Set Support Single- and multi-byte character code sets are supported. RETURN VALUE
Exit values are: 0 Successful completion. >0 Error condition occurred. AUTHOR
was developed by OSF and HP. SEE ALSO
comm(1), sort(1). STANDARDS CONFORMANCE
uniq(1)