Look

look looks for entries in a list which contain a given string as prefix

Usage
look [-bdf] [-t termchar ] string [ file ...]

Options
-b Use binary search. Requires input to be sorted.

-d Use alphanumerics only, and dictionary sorting

-f ignore case

-t stop comparisons on the given terminator character.

Environment
The command is affected by environment variables LANG, LC_ALL, and LC_CTYPE as described in the environ(7) man page.

Provided by
Most (all?) Linux distributions incorporate this from the [util-linux] project