whatis
Overview
whatis prints single-line descriptions from the man-db whatis index. Use it when you want a one-sentence reminder of what a command is without opening the full manual. Same idea as man -f.
Syntax
whatis [options] name...Common Options
| Option | Description |
|---|---|
-s list |
Only these sections (e.g. 1,8) |
-l |
Long / multi-line when available |
-r |
Interpret name as regex (implementation-dependent) |
-w |
Wildcard match |
Examples with Explanations
whatis ls
whatis passwd
whatis passwd chmod mount
whatis -s 5 passwd # file format page, not the command
man -f ls # equivalentMissing database
If you see “nothing appropriate”:
sudo mandb
# or on some systems: sudo makewhatis
whatis lsCombine with type
type mount
whatis mount
man 8 mount