The Linux and Unix Basename and Dirname Commands with Examples

When working in a Linux or Unix environment, command-line tools like basename and dirname are fundamental for handling file paths. They become especially handy when you’re writing shell scripts or automating tasks that involve navigating or manipulating directory structures. These tools are part of a powerful suite of utilities that make scripting in Linux so flexible and effective. If you’re a fan of elegant, concise Bash tricks, you might also appreciate the tips shared in 3 Bash One-Liners, which help streamline your command-line workflow.

Understanding these commands also pairs well with learning how symbolic links function, a topic we covered extensively in this article on symbolic links. Together, these utilities give you fine control over your file system paths and behaviors. In this article, we’ll go over both basename and dirname, and demonstrate practical examples that you can try right away.

What is basename?

The basename command is used to extract the file name from a given path. This is especially useful in scripts where you only need the name of the file, without the full path or extension. Here’s a breakdown of how it works:

basename /etc/passwd
passwd

This strips the directory structure and returns just the file name.

You can also remove a specific suffix by supplying it as a second argument:

basename /etc/cron.d .d
cron

This removes the .d suffix from the file name.

The basename command is particularly useful when handling files dynamically. Suppose you’re iterating over a set of files and need only their base names for logging or renaming—basename makes this trivial.

Advanced Usage of basename

You can use it to strip off more complex suffixes:

basename /path/to/file_one_two_three one_two_three
file_

basename /path/to/file_one_two_three ile_one_two_three
f

In both examples, basename removes the suffix string you specify from the file name. Note that it removes the string only if it appears at the end of the file name.

This behavior gives you the flexibility to tailor file name output as needed, which is particularly useful in automated scripts for file categorization, renaming, or version tracking.

What is dirname?

The dirname command does the inverse of basename. It strips the last component from a path and returns the directory path only. For instance:

dirname /etc/ssh/ssh_config
/etc/ssh

This command doesn’t alter the current working directory; it merely manipulates the string of the file path. It’s great for scenarios where you need to extract the directory path from a full path to pass it to another command or function.

Combining with Other Commands

Both basename and dirname are often used in scripts alongside other shell commands. For example, if you’re working with tab completion enhancements from your .inputrc configuration (which we cover in this article on smarter tab completion), you might find it convenient to use these commands to manage file paths dynamically as you tab through them.

Conclusion

Whether you’re automating a backup process, writing a log parser, or just exploring how paths are managed in Linux, basename and dirname are invaluable tools. They offer a simple interface to manipulate paths without resorting to complex string parsing.

These utilities underscore the elegance of Unix philosophy—small tools that do one thing well. When combined with other command-line tricks and techniques, they can help you build powerful, maintainable scripts. Don’t forget to explore related topics like symbolic links and smart one-liners to round out your understanding and enhance your productivity. Happy scripting!