The apropos utility searches a set of database files containing short descriptions of system commands for keywords and displays the result on the standard output. The whatis utility displays only complete word matches.

The keyword really is an extended regular expression, please read grep(1) manual page for more information about its format.

• PATH, MANPATH, MANLOCALES Used in finding the whatis database files. See manpath(1).
• PAGER Command used to page the output. The default is more-s .

The apropos utility exits 0 on success, and 1 if no keyword matched.

grep(1), makewhatis(1), man(1)