LOOK(1) BSD General Commands Manual LOOK(1)
look - display lines beginning with a given string
look [-df] [-t termchar] string [file ...]
The look utility displays any lines in file which contain string as a
If file is not specified, the file /usr/share/dict/words is used, only
alphanumeric characters are compared and the case of alphabetic charac
ters is ignored.
-b Use a binary search on the given word list. If you are ignoring
case with -f or ignoring non-alphanumeric characters with -d, the
file must be sorted in the same way. See sort(1) for more infor
mation on sorting files.
-d Dictionary character set and order, i.e. only alphanumeric char
acters are compared.
-f Ignore the case of alphabetic characters.
-t Specify a string termination character, i.e. only the characters
in string up to and including the first occurrence of termchar
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.
/usr/share/dict/words the dictionary
The original manual page stated that tabs and blank characters partici
pated in comparisons when the -d option was specified. This was incor
rect and the current man page matches the historic implementation.
look uses a linear search by default instead of a binary search, which is
what most other implementations use by default.
A look utility appeared in Version 7 AT&T UNIX.
BSD May 13, 2004 BSD