1. Create a squashfs file by adding source directories and files with the mksquashfs command:

        $ mksquashfs SOURCES compressedfs.squashfs

Sources can be wildcards, files, or folder paths.

Consider this example:

        $ sudo mksquashfs /etc test.squashfs
        Parallel mksquashfs: Using 2 processors
        Creating 4.0 filesystem on test.squashfs, block size 131072.
        [=======================================] 1867/1867 100%  

2. To mount the squashfs file to a mount point, use loopback mounting, as follows:

        # mkdir /mnt/squash
        # mount -o loop compressedfs.squashfs /mnt/squash

You can access the contents at /mnt/squashfs.