The Difference Between –rbind and –bind in Mounting

In the world of Linux, the mount command is a powerful tool that allows you to attach a filesystem located on some device to a certain directory in your directory tree. This is a process known as mounting. Among the many options available with the mount command, two that often cause confusion are --bind and --rbind. In this article, we’ll delve into the differences between these two options, providing clear explanations and examples to help you understand their usage.

Understanding the Mount Command

Before we dive into the specifics of --bind and --rbind, it’s important to understand the basics of the mount command. The mount command in Linux is used to attach a filesystem, which is located on some device, to a certain directory in your directory tree. The syntax for the mount command is as follows:

mount -t type device dir

Here, -t type is used to indicate the filesystem type, device is the storage device that contains the filesystem, and dir is the directory where the filesystem is to be attached.

The –bind Option

The --bind option is used to create a new mount point for a directory. This means it allows you to make a specific directory accessible from another location. The syntax for using --bind is as follows:

mount --bind old_directory new_directory

Here, old_directory is the directory you want to bind, and new_directory is the location where you want it to be accessible. Note that --bind does not recursively bind directories; it only binds the specific directory you specify.

The –rbind Option

The --rbind option, on the other hand, works similarly to --bind but with one key difference: it recursively binds directories. This means it will bind a directory and all of its subdirectories to a new location. The syntax for using --rbind is as follows:

mount --rbind old_directory new_directory

Again, old_directory is the directory you want to bind, and new_directory is the location where you want it to be accessible. With --rbind, all subdirectories of old_directory will also be accessible at the corresponding locations under new_directory.

Comparing –bind and –rbind

To illustrate the difference between --bind and --rbind, consider the following example. Let’s say we have a directory /home/xyz with subdirectories def and mno. If we run mount --bind /home/xyz /home/abc, the contents of xyz will be visible in abc, but def and mno will not be accessible under abc.

However, if we run mount --rbind /home/xyz /home/abc, the contents of xyz, def, and mno will all be visible and accessible under abc. This is because --rbind recursively binds the entire directory structure of xyz to abc.

Conclusion

In summary, both --bind and --rbind are useful options with the mount command that allow you to bind directories to other locations. The key difference is that --rbind recursively includes all subdirectories, while --bind does not. Understanding these options can help you manage your filesystem more effectively, making directories accessible exactly where you need them.