# man > look(1)

> **TLDR:** Display lines beginning with a prefix in a sorted file.
>
- Search for lines beginning with a specific prefix in a specific file:
  `look {{prefix}} {{path/to/file}}`
- Case-insensitively search only on alphanumeric characters:
  `look {{-f|--ignore-case}} {{-d|--alphanum}} {{prefix}} {{path/to/file}}`
- Specify a string termination character (space by default):
  `look {{-t|--terminate}} {{,}}`
- Search in `/usr/share/dict/words` (`--alphanum` and `--ignore-case` are assumed):
  `look {{prefix}}`

*Source: tldr-pages*

---

[LOOK(1)](https://www.chedong.com/phpMan.php/man/LOOK/1/markdown)                                     User Commands                                    [LOOK(1)](https://www.chedong.com/phpMan.php/man/LOOK/1/markdown)



## 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 **look** performs a binary
       search, the lines in _file_ must be sorted (where [**sort**(1)](https://www.chedong.com/phpMan.php/man/sort/1/markdown) was given the same options **-d** and/or
### -f

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

## FILES
       _/usr/share/dict/words_
           the dictionary

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

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

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

## SEE ALSO
       [**grep**(1)](https://www.chedong.com/phpMan.php/man/grep/1/markdown), [**sort**(1)](https://www.chedong.com/phpMan.php/man/sort/1/markdown)

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

## 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/>>.



util-linux 2.37.2                            2021-06-02                                      [LOOK(1)](https://www.chedong.com/phpMan.php/man/LOOK/1/markdown)