display lines beginning with a given string


look [options] string[file]


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


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


" /usr/share/dict/words "4 the dictionary

" /usr/share/dict/web2 "4 the alternative dictionary


-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,--terminatecharacter 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.


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


The look command is part of the util-linux package and is available from https://www.kernel.org/pub/linux/utils/util-linux/.


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) was given the same options -dand/or-fthat 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.


grep(1), sort(1)

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