The syntax for using the mkisofs command for creating an empty ISO image ismkisofs -o . assuming you are currently in an empty directory. E.g. mkisofs -o test.iso . will create an empty ISO image called test.iso.

The syntax for copying a file to an already created ISO image is growisofs -M -graft-points =. E.g. growisofs -M test.iso -graft-points /folder/new.txt=old.txt will copy the file old.txt to the test.iso image, place it under the directory “folder” and rename it to new.txt.

The command to mount the ISO image is mount -t iso9660 -o loop. E.g.mount -t iso9660 -o loop test.iso /mnt/cd will mount test.iso ISO image to the directory /mnt/cd.

To unmount: umount /mnt/cd

Using ISOLINUX

http://syslinux.zytor.com/wiki/index.php/ISOLINUX

mkdir CD_root
cd CD_root
mkdir isolinux
cp /usr/lib/syslinux/isolinux.bin isolinux/
vi isolinux/isolinux.cfg

cd ..
mkdir images
mkdir kernel
cp /usr/lib/syslinux/memdisk kernel/

cd ..
mkisofs -o output.iso 
    -b isolinux/isolinux.bin -c isolinux/boot.cat 
    -no-emul-boot -boot-load-size 4 -boot-info-table CD_root

The ISO file can be burned to create a bootable CD.