LOOK(1)                   BSD General Commands Manual                  LOOK(1)

     look — display lines beginning with a given string

     look [-bdf] [-t termchar] string [file ...]

     The look utility displays any lines in file which contain string as a

     If file is not specified, the file /usr/share/dict/words is used, only
     alphanumeric characters are compared and the case of alphabetic charac‐
     ters 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 char‐
             acters 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.

     The LANG, LC_ALL and LC_CTYPE environment variables affect the execution
     of the look utility.  Their effect is described in environ(7).

     /usr/share/dict/words  the dictionary

     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.

     The original manual page stated that tabs and blank characters partici‐
     pated 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.

     grep(1), sort(1)

     A look utility appeared in Version 7 AT&T UNIX.

     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