Linux Shell Scripting Cookbook - Third Edition

How to do it...

To create a 1 GB ext4 filesystem in a file, follow these steps:

1. Use dd to create a 1 GB file:

        $ dd if=/dev/zero of=loobackfile.img bs=1G count=1
        1024+0 records in
        1024+0 records out
        1073741824 bytes (1.1 GB) copied, 37.3155 s, 28.8 MB/s

 The size of the created file exceeds 1 GB because the hard disk is a block device, and hence, storage must be allocated by integral multiples of blocks size.

2. Format the 1 GB file to ext4 using the mkfs command:

        $ mkfs.ext4 loopbackfile.img

3. Check the file type with the file command:

        $ file loobackfile.img
        loobackfile.img: Linux rev 1.0 ext4 filesystem data,   
        UUID=c9d56c42-   
        f8e6-4cbd-aeab-369d5056660a (extents) (large files) (huge files)

4. Create a mount point and mount the loopback ...