Lesson 71: whereis Command
In this lesson, you'll learn how to use the whereis command to locate the binary, source code, and manual page files for any command on your Linux system and how to use it to diagnose path conflicts, verify installations, and audit command locations in scripts.
The whereis command searches a fixed set of standard directories defined by the system (such as /usr/bin, /usr/sbin, /usr/share/man, and /usr/src) rather than walking your entire filesystem or relying on the $PATH variable.
This makes it significantly faster than find for locating command-related files, and more thorough than which because it returns binary, source, and man page locations in a single shot.
Syntax
whereis [OPTIONS] COMMAND [COMMAND...]
Multiple command names can be passed in a single call.
Options
| Option | Description |
|---|---|
-b |
Search for binaries only |
-m |
Search for manual pages only |
-s |
Search for source files only |
-u |
Show commands that have unusual (missing) entries |
-B <dir> |
Limit binary search to the specified directory |
-M <dir> |
Limit manual page search to the specified directory |
-S <dir> |
Limit source search to the specified directory |
-l |
List the directories that whereis searches |
-h, --help |
Display help and exit |
-V, --version |
Display version information and exit |
Understanding the whereis Output
whereis mkdir
mkdir: /usr/bin/mkdir /usr/share/man/man1/mkdir.1.gz
The output format is always:
COMMAND: [binary path] [source path] [man page path]
Fields that are not found are simply omitted — no error is shown for missing entries. This means a result with only a binary path indicates no source or man page was found in the standard search directories.
Note: whereis only searches a predefined list of standard system directories. If a command was installed to a non-standard location (such as /opt, ~/.local/bin, or a custom prefix), whereis may not find it. Use find or which in those cases.
1. Locate Files for a Single Command
whereis fswatch
fswatch: /usr/bin/fswatch /usr/share/man/man1/fswatch.1.gz
whereis rm
rm: /usr/bin/rm /usr/share/man/man1/rm.1.gz
whereis mkdir
mkdir: /usr/bin/mkdir /usr/share/man/man1/mkdir.1.gz
For standard system commands, whereis returns both the binary path and the compressed man page location. The .gz extension on the man page is normal — man decompresses it automatically when you run man mkdir.
2. Locate Files for Multiple Commands at Once
whereis ls cp mv rm
ls: /usr/bin/ls /usr/share/man/man1/ls.1.gz
cp: /usr/bin/cp /usr/share/man/man1/cp.1.gz
mv: /usr/bin/mv /usr/share/man/man1/mv.1.gz
rm: /usr/bin/rm /usr/share/man/man1/rm.1.gz
Passing multiple command names in a single call is faster and cleaner than running whereis repeatedly. Use this when auditing a set of commands or verifying that a group of tools is all properly installed.