LOOK(1) BSD General Commands Manual LOOK(1)


look − display lines beginning with a given string


look [−dfa] [−t termchar] 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) got the same options −d and/or −f that look is invoked with).

If file is not specified, the file /usr/dict/words is used, only alphanumeric characters are compared and the case of alphabetic characters is ignored.


      −d’        Dictionary character set and order, i.e. only alphanumericcharacters are compared.

−f’ Ignore the case of alphabetic characters.

−a’ Use the alternate dictionary /usr/dict/web2

−t’ Specify a string termination character, i.e. only the characters in string up to and including the first occurrence of termchar are compared.

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 dictionary
the alternate dictionary


grep(1), sort(1)


The original manual page stated that tabs and blank characters participated in comparisons when the −d option was specified. This was incorrect and the current man page matches the historic implementation.


Look appeared in Version 7 AT&T Unix.

BSD June 14, 1993 BSD