To mount an iso file to copy files.
open your terminal
First you must have a folder to mount the iso file to, type:
sudo mkdir /media/isofile
now you mount it with some special options.
sudo mount myiso.iso /media/isofile/ -t iso9660 -o loop
Now your files will be mounted in /media/isofile/ folder. They will be read only so you will not be able to add to them.
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