How to create an ISO image from an optical disc on Linux

Creating an ISO image from a data CD, DVD, or Blu-ray turns the disc into a single file that is easier to archive, checksum, mount, and reuse than the original media. The saved image can be attached to a virtual machine, copied to another system, or written back to removable media without returning to the physical disc.

On Linux, a data disc usually appears as a read-only block device such as /dev/sr0. Reading that device with dd copies the disc data into an .iso file, and the saved image can then be inspected or mounted with the same filesystem-aware tools used for any other ISO 9660 image.

This workflow is for data discs that the kernel exposes as a normal optical drive device. Audio CDs, mixed-mode discs, damaged media, and copy-protected discs often need different tools, the destination filesystem needs free space at least equal to the disc size, and reading the optical device usually requires sudo privileges.

Related: How to mount and access ISO files in Linux
Related: How to create a bootable USB drive from an ISO image on Linux

Steps to create an ISO image from an optical disc in Linux:

  1. List block devices and identify the optical drive device name. 
    $ lsblk --list --output NAME,SIZE,TYPE,RO,MOUNTPOINTS
NAME        SIZE TYPE RO MOUNTPOINTS
nvme0n1   476.9G disk  0
nvme0n1p1    1G part  0 /boot/efi
nvme0n1p2 475.9G part  0 /
sr0         4.3G rom   1

    Use the read-only rom entry for the inserted disc. Optical drives commonly appear as /dev/sr0, but systems with multiple drives can expose /dev/sr1 or another /dev/sr* path instead.

  2. Create a destination directory for the image file. 
    $ mkdir -p ~/iso-backups
  3. Copy the optical disc into an .iso file with dd. 
    $ sudo dd if=/dev/sr0 of=~/iso-backups/archive-disc.iso bs=2048 status=progress conv=fsync
185+0 records in
185+0 records out
378880 bytes (379 kB, 370 KiB) copied, 0.0257333 s, 14.7 MB/s

    Replace /dev/sr0 with the actual optical device from lsblk. status=progress prints transfer statistics while the copy is running, and conv=fsync waits for the image file to be flushed before dd exits.

    If dd reports an input/output error, treat the saved file as incomplete and retry only after cleaning the disc, trying another drive, or switching to a recovery-oriented workflow.

  4. Confirm that the saved file is recognized as an ISO image. 
    $ file ~/iso-backups/archive-disc.iso
/home/operator/iso-backups/archive-disc.iso: ISO 9660 CD-ROM filesystem data 'ARCHIVE_DISC'

    The volume label shown by file comes from the disc and can differ from this example.

  5. Create a temporary mountpoint and mount the image read-only for a quick content check. 
    $ sudo mkdir -p /mnt/archive-disc
$ sudo mount -o loop,ro ~/iso-backups/archive-disc.iso /mnt/archive-disc

    Loop-mounting the image confirms that the saved file can be read like the original optical disc without putting the media back in the drive.

  6. List the top-level contents of the mounted image to confirm that the expected files are present. 
    $ ls -1 /mnt/archive-disc
README.txt
docs
  7. Unmount the image when the verification check is complete. 
    $ sudo umount /mnt/archive-disc