look(1) — Commands
NAME
look − Finds lines in a sorted list
SYNOPSIS
look [−df] [−tcharacter] string [file]
The look command prints all lines in a sorted file that begin with string.
OPTIONS
−dUses dictionary order; only letters, digits, tabs, and spaces are used in comparisons.
−fSearches without regard to case; treats uppercase and lowercase as equivalent.
−tcharacter
Ignores character and characters following it in the search string. If you specify look -tC ABCDE, the string ABCDE would become (in effect) AB, with CDE being ignored. This option is primarily for shell scripts, in which more than one string is being processed.
DESCRIPTION
If no file is specified, look searches in the system word list /usr/share/dict/words, with the options −df assumed by default.
The look command uses binary search.
The −d and −f options affect comparisons as in sort.
NOTES
In order to use the −f option, you must first sort file with the sort −f command; otherwise, look displays only lowercase items.
If you do not specify −f, but specify a file (such as /usr/share/dict/words) that has been sorted with sort −f, look may not produce any output.
EXAMPLES
1.To search a sorted file called sortfile for all lines that begin with the string as, enter:
look as sortfile
2.To search the system word list for all words beginning with smi, enter:
look smi
This might result in:
smile
smirk
smith
smithereens
Smithfield
Smithson
smithy
smitten
FILES
/usr/share/dict/words
System word list.