LOOK(1) BSD General Commands Manual LOOK(1) NAME look — display lines beginning with a given string SYNOPSIS look [-bdf] [-t termchar] string [file ...] DESCRIPTION The look utility displays any lines in file which contain string as a prefix. 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. The following options are available: -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. Please note that these options are the default if no filename is given. See sort(1) for more information 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 are compared. ENVIRONMENT The LANG, LC_ALL and LC_CTYPE environment variables affect the execution of the look utility. Their effect is described in environ(7). FILES /usr/share/dict/words the dictionary EXIT STATUS 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. COMPATIBILITY 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. SEE ALSO grep(1), sort(1) HISTORY A look utility appeared in Version 7 AT&T UNIX. BUGS Lines are not compared according to the current locale's collating order. Input files must be sorted with LC_COLLATE set to ‘C’. BSD July 17, 2004 BSD