#To make an ISO from your CD/DVD

dd if=/dev/dvd of=dvd.iso # for dvd
dd if=/dev/cdrom of=cd.iso # for cdrom
dd if=/dev/scd0 of=cd.iso # if cdrom is scsi

#To make an ISO from files on hard drive, create a directory which holds the files you want.
#Then use the mkisofs command.

mkisofs -o /tmp/cd.iso /tmp/directory/

Create ISO files in Linux

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