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Command: look | Section: 1 | Source: FreeBSD | File: look.1.gz
LOOK(1) FreeBSD General Commands Manual LOOK(1)
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 `xylen' 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
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'.
FreeBSD 14.1-RELEASE-p8 December 29, 2020 FreeBSD 14.1-RELEASE-p8