How to use the command realpath (with examples)

Realpath is a command that is used to display the resolved absolute path for a file or directory. It is a useful tool for working with files and directories, especially when dealing with symbolic links.

Use case 1: Display the absolute path for a file or directory

Code:

realpath path/to/file_or_directory

Motivation: This use case is helpful when you want to quickly find the absolute path of a file or directory. It can be useful for various purposes, such as troubleshooting, scripting, or simply understanding the exact location of a file or directory.

Explanation: In this use case, you need to provide the path to the file or directory for which you want to obtain the absolute path. Realpath will resolve any symbolic links and display the absolute path.

Example output:

$ realpath documents/example.txt
/home/user/documents/example.txt

Use case 2: Require all path components to exist

Code:

realpath --canonicalize-existing path/to/file_or_directory

Motivation: Sometimes, you may want to ensure that all the components of the path exist, especially when working with scripts or applications that require access to specific files or directories. Using the --canonicalize-existing option with realpath will only return the resolved absolute path if all the path components exist.

Explanation: The --canonicalize-existing option tells realpath to require all the path components to exist before resolving the absolute path. If any component of the path doesn’t exist, realpath will not resolve it.

Example output:

$ realpath --canonicalize-existing /path/to/non_existent_file
realpath: /path/to/non_existent_file: No such file or directory

Use case 3: Resolve “..” components before symlinks

Code:

realpath --logical path/to/file_or_directory

Motivation: When working with paths that contain “..” components, which refers to the parent directory, realpath can be used to resolve those components before resolving symbolic links. This ensures that the resulting path is accurate and doesn’t include any unexpected behavior due to symbolic links.

Explanation: The --logical option tells realpath to resolve any “..” components before resolving symbolic links. This is helpful when you want to obtain an accurate path that doesn’t include any potential surprises from symbolic links.

Example output:

$ realpath --logical /path/to/symlink/../file.txt
/path/to/file.txt

Use case 4: Disable symlink expansion

Code:

realpath --no-symlinks path/to/file_or_directory

Motivation: In some cases, you may want to obtain the absolute path of a symbolic link itself, rather than resolving it to the target file or directory. By using the --no-symlinks option with realpath, you can disable symlink expansion and obtain the absolute path of the symbolic link itself.

Explanation: The --no-symlinks option tells realpath to disable symlink expansion and return the absolute path of the symbolic link itself, rather than its target.

Example output:

$ realpath --no-symlinks /path/to/symlink
/path/to/symlink

Use case 5: Suppress error messages

Code:

realpath --quiet path/to/file_or_directory

Motivation: When executing realpath in a script or automation, you may want to suppress any error messages to keep the output clean and focused. The --quiet option allows you to run realpath without displaying any error messages.

Explanation: The --quiet option tells realpath to suppress error messages. This can be useful in scripts or automation workflows where you don’t want any potential error messages to clutter the output.

Example output:

$ realpath --quiet /path/to/non_existent_file

(Note: No output is displayed when using the --quiet option.)

Conclusion:

Realpath is a versatile command that can be used to obtain resolved absolute paths for files and directories. The various options it provides offer flexibility for different use cases, such as requiring existing path components, resolving “..” components before symlinks, disabling symlink expansion, and suppressing error messages. By understanding and using these different use cases, you can effectively work with paths and symbolic links in your command-line workflows.