How to open and access ISO images without burning them to a disc in Linux

ISO images are digital copies of optical discs, like CDs, DVDs, or Blu-ray Discs, commonly used for archiving purposes. These image files typically have the extensions .iso or .img and follow the ISO 9660 filesystem format.

In Linux, you can view and copy the contents of an ISO image without burning it to an optical disc by mounting the image file to a directory. This can be done from the terminal.

1. Create a temporary directory to mount the ISO file.

   $ mkdir temp

2. Verify that the ISO image file is in the correct format.

   $ file ubuntu-19.10-live-server-amd64.iso
   ubuntu-19.10-live-server-amd64.iso: DOS/MBR boot sector; partition 2 : ID=0xef, start-CHS (0x3ff,254,63), end-CHS (0x3ff,254,63), startsector 1391610, 7936 sectors

3. Mount the ISO image file to the temporary folder using the iso9660 filesystem type.

   $ sudo mount -t iso9660 ubuntu-19.10-live-server-amd64.iso temp/
   [sudo] password for user:
   mount: /home/user/temp: WARNING: device write-protected, mounted read-only.

   The ISO image is mounted as read-only, thus the content could only be viewed or copied over to different location.

4. Explore the contents of the ISO image file.

   $ ls -l temp/
   total 76
   dr-xr-xr-x 1 root root  2048 Oct 17 13:33 boot
   dr-xr-xr-x 1 root root  2048 Oct 17 13:34 casper
   dr-xr-xr-x 1 root root  2048 Oct 17 13:33 dists
   dr-xr-xr-x 1 root root  2048 Oct 17 13:33 EFI
   dr-xr-xr-x 1 root root  2048 Oct 17 13:33 install
   dr-xr-xr-x 1 root root 34816 Oct 17 13:33 isolinux
   -r--r--r-- 1 root root 25363 Oct 17 13:34 md5sum.txt
   dr-xr-xr-x 1 root root  2048 Oct 17 13:33 pics
   dr-xr-xr-x 1 root root  2048 Oct 17 13:33 pool
   dr-xr-xr-x 1 root root  2048 Oct 17 13:33 preseed
   -r--r--r-- 1 root root   232 Oct 17 13:33 README.diskdefines
   lr-xr-xr-x 1 root root     1 Oct 17 13:33 ubuntu -> .

5. Copy or view the desired contents from the ISO image file.

   $ head temp/dists/stable/Release
   Origin: Ubuntu
   Label: Ubuntu
   Suite: eoan
   Version: 19.10
   Codename: eoan
   Date: Thu, 17 Oct 2019 12:37:49 UTC
   Architectures: amd64 i386
   Components: main restricted
   Description: Ubuntu Eoan 19.10
   Acquire-By-Hash: yes
6. Leave the mount directory.

   $ cd

7. Unmount the ISO file from the mount directory.

   $ sudo umount temp/

8. Delete the temporary mount directory.

   $ rmdir temp/