# look

## NAME



           look - display lines beginning with a given string
    


## SYNOPSIS



           **look**[options] _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 (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



           **-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



           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



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


## FILES



           _/usr/share/dict/words_
               the dictionary
    
           _/usr/share/dict/web2_
               the alternative dictionary
    


## EXAMPLES



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


## AVAILABILITY



           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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