NAME
look – display lines beginning with a given string
SYNOPSIS
look [-df] [-t termchar] string [file ...]
DESCRIPTION
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.
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.
The following options are available:
- -d, --alphanum
-
Dictionary character set and order, i.e., only alphanumeric characters are compared.
- -f, --ignore-case
-
Ignore the case of alphabetic characters.
- -t, --terminate termchar
-
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.
EXAMPLES
Look for lines starting with ‘xylene’ in the file /usr/share/dict/words:
$ look xylen xylene xylenol xylenyl
Same as above, but do not consider any characters in string beyond the first ‘e’. Note that -f is implicit since we are searching the default file /usr/share/dict/words:
$ look -t e xylen Xyleborus xylem xylene xylenol xylenyl xyletic
COMPATIBILITY
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.
The -a and --alternative flags are ignored for compatibility.
SEE ALSO
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’.