look

LOOK(1)                      General Commands Manual                     LOOK(1)

NAME
     look – display lines beginning with a given string

SYNOPSIS
     look [-df] [-t termchar] string [file ...]

DESCRIPTION
     The look utility displays any lines in file which contain string as a
     prefix.  As look performs a binary search, the lines in file must be
     sorted.

     If file is not specified, the file /usr/share/dict/words is used, only
     alphanumeric characters are compared and the case of alphabetic characters
     is ignored.

     The following options are available:

     -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 incorrect and
     the current man page matches the historic implementation.

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’.

macOS 12.1                        July 17, 2004                       macOS 12.1