look(1) — Linux manual page
LOOK(1) User Commands LOOK(1)
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
Print version 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 the
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), sort(1)
REPORTING BUGS
For bug reports, use the issue tracker at
https://github.com/util-linux/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/>. 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
2024-06-14. (At that time, the date of the most recent commit
that was found in the repository was 2024-06-10.) 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