look(1) [linux man page]
LOOK(1) BSD General Commands Manual LOOK(1) NAME
look -- display lines beginning with a given string SYNOPSIS
look [-bdf] [-t termchar] string [file ...] DESCRIPTION
The look utility displays any lines in file which contain string as a prefix. If file is not specified, the file /usr/share/dict/words is used, only alphanumeric characters are compared and the case of alphabetic char- acters is ignored. The following options are available: -b Use a binary search on the given word list. If you are ignoring case with -f or ignoring non-alphanumeric characters with -d, the file must be sorted in the same way. Please note that these options are the default if no filename is given. See sort(1) for more information on sorting files. -d Dictionary character set and order, i.e., only alphanumeric characters are compared. -f Ignore the case of alphabetic characters. -t Specify a string termination character, i.e., only the characters in string up to and including the first occurrence of termchar are compared. ENVIRONMENT
The LANG, LC_ALL and LC_CTYPE environment variables affect the execution of the look utility. Their effect is described in environ(7). FILES
/usr/share/dict/words the dictionary EXIT STATUS
The look utility exits 0 if one or more lines were found and displayed, 1 if no lines were found, and >1 if an error occurred. COMPATIBILITY
The original manual page stated that tabs and blank characters participated in comparisons when the -d option was specified. This was incor- rect and the current man page matches the historic implementation. look uses a linear search by default instead of a binary search, which is what most other implementations use by default. SEE ALSO
grep(1), sort(1) HISTORY
A look utility appeared in Version 7 AT&T UNIX. BUGS
Lines are not compared according to the current locale's collating order. Input files must be sorted with LC_COLLATE set to 'C'. BSD
July 17, 2004 BSD
Check Out this Related 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
December 17, 2009 BSD