LOOK(1)                         User Commands                        LOOK(1)

NAME         top

       look - display lines beginning with a given string

SYNOPSIS         top

       look [options] string [file]

DESCRIPTION         top

       The look utility displays any lines in file which contain string.  As
       look performs a binary search, the lines in file must be sorted
       (where sort(1) was given the same options -d and/or -f that look is
       invoked with).

       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.

OPTIONS         top

       -a, --alternative
              Use the alternative dictionary file.

       -d, --alphanum
              Use normal dictionary character set and order, i.e., only
              blanks and alphanumeric characters are compared.  This is on
              by default if no file is specified.

              Note that blanks have been added to dictionary character set
              for compatibility with sort -d command since version 2.28.

       -f, --ignore-case
              Ignore the case of alphabetic characters.  This is on by
              default if no file is specified.

       -t, --terminate character
              Specify a string termination character, i.e., only the
              characters in string up to and including the first occurrence
              of character are compared.

       -V, --version
              Display version information and exit.

       -h, --help
              Display help text and exit.

       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.

ENVIRONMENT         top

              Path to a dictionary file.  The environment variable has
              greater priority than the dictionary path defined in FILES

FILES         top

           the dictionary

           the alternative dictionary

HISTORY         top

       The look utility appeared in Version 7 AT&T Unix.

EXAMPLE         top

              sort -d /etc/passwd -o /tmp/look.dict
              look -t: root:foobar /tmp/look.dict

SEE ALSO         top

       grep(1), sort(1)

AVAILABILITY         top

       The look command is part of the util-linux package and is available

COLOPHON         top

       This page is part of the util-linux (a random collection of Linux
       utilities) project.  Information about the project can be found at 
       ⟨⟩.  If you have a
       bug report for this manual page, send it to  This page was obtained from the
       project's upstream Git repository
       ⟨git://⟩ on
       2020-05-27.  (At that time, the date of the most recent commit that
       was found in the repository was 2020-05-27.)  If you discover any
       rendering problems in this HTML version of the page, or you believe
       there is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to

util-linux                        June 2011                          LOOK(1)