whereis

TLDR

Locate binary, source, and man pages for SSH

$ whereis ssh

Locate binary and man pages only for ls

$ whereis -bm ls

Locate source of gcc and man pages for Git

$ whereis -s gcc -m git

Locate binaries for gcc in /usr/bin/ only

$ whereis -b -B /usr/bin/ -f gcc

Locate unusual binaries (more or less than one binary)

$ whereis -u *

Locate binaries with unusual manual entries

$ whereis -u -m *

SYNOPSIS

whereis [-bmsuf] [-BMS directory... -f] name...

whereis locates the binary, source, and manual page files for a command by searching a set of standard locations. Unlike which, it searches predefined directories rather than the PATH variable, and can find source and documentation files.
The command uses hardcoded directory lists that may include /bin, /sbin, /usr/bin, /usr/share/man, /usr/src, and similar system directories. Use -l to see the actual search paths on your system.

PARAMETERS

-b

Search only for binaries

-m

Search only for manual sections

-s

Search only for sources

-u

Search for unusual entries (commands with more than one binary, or no manual)

-B list

Limit binary search to specified directories

-M list

Limit manual search to specified directories

-S list

Limit source search to specified directories

-f

Terminate directory list (required when using -B, -M, or -S)

-l

Output list of effective search paths

CAVEATS

May not find binaries in non-standard locations (use which for PATH-based lookup). Source directories are often empty on binary distributions. Results depend on the compiled-in search paths which vary between distributions.

HISTORY

Originated in 3BSD Unix (1979) at UC Berkeley. One of the early Berkeley additions to Unix for locating program components. Part of util-linux on modern Linux systems.