look - display lines beginning with a given string
look [options] string [file]
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.
Note that blanks have been added to dictionary character set for compatibility with sort -d command since version 2.28.
-t, --terminate character
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.
The look utility appeared in Version 7 AT&T Unix.
sort -d /etc/passwd -o /tmp/look.dict look -t: root:foobar /tmp/look.dict
For bug reports, use the issue tracker at <https://github.com/util-linux/util-linux/issues>.
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/>.