Common CD mount points are
/mnt/cdrom and common DVD mount points are
If the mount point does not exist, create it:
mount -t iso9660 -o ro /dev/cdrom /mnt/cdrom
If you cannot mount because
the device is already mounted or directory busy
perhaps the mount point
/mnt/cdrom is your current directory. You have to change the directory to somewhere else in order to be able to mount to it.
Unmount and eject
Exit the directory
/mnt/cdrom and execute:
umount /mnt/cdrom eject
Or simply run:
If you are unable to unmount your previously mounted CD-ROM, make sure that you are not in the directory where your CD-ROM is mounted or that some other application is not using it.
If you are still having problems to unmount your CD-ROM medium you can use
fuser command to kill all related processes using your device.
fuser -mk /dev/hdc eject
Never use the above command on devices mounted read/write unless you are sure what you are doing.