How to Add Files to an ISO Image in Linux

1. Launch Terminal.
2. Create a mounting point for the ISO image using the following command:
sudo mkdir /media/iso
3. Mount the ISO image with the following command, making sure to specify the location on the hard drive of the ISO file you wish to edit:
sudo mount -o loop /location/of/ISO/file.iso /media/iso
4. Create a directory to copy the ISO contents with the following command (you can change the destination directory to whatever you want):
sudo mkdir /mnt/test
5. Copy the contents of the mounted ISO with the following command:
sudo cp /media/iso/* /mnt/test
6. Unmount the ISO file with the following command:
sudo unmount /media/iso
7. Copy the files you wish to add to the ISO image using your file manager.
8. Create a new ISO image containing the additional files with the following command, making certain to execute the command from within the '/mnt/test' directory (the ISO image file name and destination can be changed to whatever you prefer):
mkisofs -r -o /home/newfile.iso