look(1) — Linux manual page

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 a prefix. 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.

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

       -V, --version
           Display version and exit.

EXIT STATUS         top

       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

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

FILES         top

       /usr/share/dict/words
           the dictionary

       /usr/share/dict/web2
           the alternative dictionary

HISTORY         top

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

EXAMPLES         top

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

SEE ALSO         top

       grep(1), sort(1)

REPORTING BUGS         top

       For bug reports, use the issue tracker
       <https://github.com/util-linux/util-linux/issues>.

AVAILABILITY         top

       The look command is part of the util-linux package which can be
       downloaded from Linux Kernel Archive
       <https://www.kernel.org/pub/linux/utils/util-linux/>. This page is
       part of the util-linux (a random collection of Linux utilities)
       project. Information about the project can be found at 
       ⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩. If you have a
       bug report for this manual page, send it to
       util-linux@vger.kernel.org. This page was obtained from the
       project's upstream Git repository
       ⟨git://git.kernel.org/pub/scm/utils/util-linux/util-linux.git⟩ on
       2025-08-11. (At that time, the date of the most recent commit that
       was found in the repository was 2025-08-05.) 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 man-pages@man7.org

util-linux 2.42-start-521-ec46  2025-08-09                        LOOK(1)

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