whereis is a command on Unix and Unix-like operating systems used to locate some special files of a command like the binary file, source and manual page files. The whereis utility was first included with 2BSD, dating back to 1979.
The whereis man page provides the following sample usage:
% # Find all files in /usr/bin which are not documented in /usr/man/man1 with source in /usr/src:
% cd /usr/bin
% whereis -u -M /usr/man/man1 -S /usr/src -f *
The Unix type command is similar, but it identifies aliases.
Modern versions of Microsoft Windows feature a similar command: where.
It's also similar to the where utility in Multics.
I'm pretty sure we got it in early 79, so I clearly rewrote it at some point if the dates show later
[…] the Where command […] is equivalent to using the Search option in the Start menu.