whereis Command Linux: Complete Guide to Locate Binary, Source and Manual Pages

The whereis command is a powerful Linux utility that helps system administrators and developers quickly locate binary executables, source files, and manual pages for commands and programs. Unlike other search commands, whereis provides a fast and efficient way to find specific types of files without searching the entire filesystem.

What is the whereis Command?

The whereis command searches for files in a restricted set of locations, making it much faster than commands like find or locate. It specifically looks for:

• Binary executables – The actual program files
• Source files – Source code files
• Manual pages – Documentation files

This targeted approach makes whereis ideal when you need to quickly understand where a program is installed or find its documentation.

Basic Syntax and Usage

The basic syntax of the whereis command is:

whereis [options] filename

Let’s start with a simple example:

$ whereis ls
ls: /bin/ls /usr/share/man/man1/ls.1.gz

This output shows that the ls command’s binary is located at /bin/ls and its manual page is at /usr/share/man/man1/ls.1.gz.

Command Options and Flags

The whereis command offers several options to refine your search:

-b (Binary Only)

Use the -b option to search only for binary files:

$ whereis -b python
python: /usr/bin/python /usr/bin/python3.8 /usr/bin/python3.9

-m (Manual Pages Only)

The -m option searches only for manual pages:

$ whereis -m gcc
gcc: /usr/share/man/man1/gcc.1.gz

-s (Source Files Only)

Use -s to search for source files:

$ whereis -s bash
bash: /usr/src/bash

-u (Unusual Entries)

The -u option finds files that don’t have the expected number of entries:

$ whereis -u -m -s *

Advanced Options

Custom Search Paths

You can specify custom search directories using these options:

• -B directory – Set binary search path
• -M directory – Set manual page search path
• -S directory – Set source search path

$ whereis -B /usr/local/bin -b python
python: /usr/local/bin/python3.9

Limiting Search Scope

Use -f to terminate the directory list and begin the file list:

$ whereis -B /bin -f ls cat
ls: /bin/ls
cat: /bin/cat

Practical Examples

Finding Complete Information About a Command

To get comprehensive information about where a command’s files are located:

$ whereis vim
vim: /usr/bin/vim /usr/bin/vim.basic /usr/bin/vim.tiny /etc/vim /usr/share/vim /usr/share/man/man1/vim.1.gz

This shows the binary locations, configuration directory, and manual page for vim.

Checking Multiple Commands

You can check multiple commands simultaneously:

$ whereis grep sed awk
grep: /bin/grep /usr/share/man/man1/grep.1.gz
sed: /bin/sed /usr/share/man/man1/sed.1.gz
awk: /usr/bin/awk /usr/share/man/man1/awk.1.gz

Finding Development Tools

Locate development tools and their documentation:

$ whereis -b -m gcc make
gcc: /usr/bin/gcc /usr/share/man/man1/gcc.1.gz
make: /usr/bin/make /usr/share/man/man1/make.1.gz

Comparing whereis with Other Commands

whereis vs which

While which only shows the path to the executable, whereis provides more comprehensive information:

$ which python
/usr/bin/python

$ whereis python
python: /usr/bin/python /usr/bin/python2.7 /usr/share/man/man1/python.1.gz

whereis vs locate

The locate command searches the entire filesystem database, while whereis searches specific directories:

$ locate bash | head -5
/bin/bash
/etc/bash.bashrc
/etc/bash_completion
/etc/bash_completion.d
/usr/share/doc/bash

$ whereis bash
bash: /bin/bash /etc/bash.bashrc /usr/share/man/man1/bash.1.gz

Common Use Cases

System Administration

System administrators often use whereis to:

• Verify software installation locations
• Find configuration files
• Locate documentation for troubleshooting

$ whereis apache2
apache2: /usr/sbin/apache2 /etc/apache2 /usr/share/apache2 /usr/share/man/man8/apache2.8.gz

Development Environment Setup

Developers use whereis to locate development tools:

$ whereis node npm
node: /usr/bin/node /usr/include/node /usr/share/man/man1/node.1.gz
npm: /usr/bin/npm /usr/share/man/man1/npm.1

Package Management

Before installing or removing packages, check their current locations:

$ whereis git
git: /usr/bin/git /usr/share/man/man1/git.1.gz

Troubleshooting Common Issues

No Results Found

If whereis returns no results, the file might not be installed or located in standard directories:

$ whereis nonexistentcommand
nonexistentcommand:

Partial Results

Sometimes you might see only binary or manual pages. This is normal and indicates that not all file types are available:

$ whereis somecommand
somecommand: /usr/bin/somecommand

Performance Considerations

The whereis command is optimized for speed because it:

• Searches only predefined directories
• Doesn’t traverse the entire filesystem
• Uses built-in path knowledge
• Doesn’t rely on database updates like locate

Best Practices

Use Specific Options

When you know what you’re looking for, use specific options:

# Only need the binary location
$ whereis -b python

# Only need documentation
$ whereis -m python

Combine with Other Commands

Use whereis output with other commands:

$ ls -la $(whereis -b python | cut -d: -f2)

Script Integration

In shell scripts, use whereis to verify dependencies:

#!/bin/bash
if [ -z "$(whereis -b git | cut -d: -f2)" ]; then
    echo "Git is not installed"
    exit 1
fi

Alternative Commands

While whereis is excellent for its specific use case, consider these alternatives:

• which – Find executable location in PATH
• type – Show command type and location
• locate – Find files using database
• find – Search filesystem in real-time

Conclusion

The whereis command is an essential tool for Linux users who need to quickly locate system files, binaries, and documentation. Its speed and targeted search make it invaluable for system administration, development, and troubleshooting tasks. By understanding its various options and use cases, you can efficiently manage and navigate your Linux system.

Whether you’re setting up a development environment, troubleshooting system issues, or simply exploring your system’s file structure, whereis provides the quick answers you need without the overhead of more comprehensive search tools.