UnionFS creates a unified seamless filesystem by transparently overlaying files and directories from separate filesystems. Each participant directory is referred to as a branch, and when mounting branches, we can set priorities and access modes. Thus, in this short guide, we will consider how to get it installed in Ubuntu 22.04. Furthermore, you’ll learn how to overlay two files with UnionFs.
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Prerequisites to Overlaying Files With UnionFs
To overlay two files using UnionFs, you need the following:
- A Linux Machine (Ubuntu 18 or Higher)
- A user account with sudo privileges
Step 1: Update the package index
you can use the command below :
apt-get updateStep 2: Install Unionfs
Install the appropriate UnionFs packages specific to your distribution. Hence, you can use the command below:
sudo apt install -y unionfs-fuseStep 3: Create two separate directories (branches) with two files each respectively
Once you’ve installed UnionFs on your Linux system, proceed to overlay the two files by creating directories. So, the two directories will serve as a source for the overlay.
mkdir dir1
touch dir1/f1
touch dir1/f2
mkdir dir2
touch dir2/f3
touch dir2/f4
Step 4: Let’s create an empty directory to overlay files
To overlay the two directories, we need to mount them using UnionFs. Meanwhile, this empty directory is where union will be mounted and we can do this with the command as shown below:
mkdir union
Step 5: Mount the two branches
To successfully overlay files with UnionFs, you need to ensure you mount them. Therefore, we can overlay the two branches on top of each with the command :
unionfs dir1/:dir2/ union/
Step 6: Verify the files are overlayed with UnionFs
Afterward, verify the files. We can do this with the command :
ls union/
Summary
Congratulations! Now, you can overlay files with UnionFs. Furthermore, we can use Unionfs to over several files by following the steps as shown above
