# grub-mkrescue --xorriso=/root/xorriso-1.5.4/xorriso/xorriso -o myos.iso isodir
GNU xorriso 1.5.4.pl02 : RockRidge filesystem manipulator, libburnia project.

Drive current: -outdev 'stdio:myos.iso'
Media current: stdio file, overwriteable
Media status : is blank
Media summary: 0 sessions, 0 data blocks, 0 data,  235g free
Added to ISO image: directory '/'='/tmp/grub.1GStHe'
xorriso : UPDATE :       3 files added in 1 seconds
Added to ISO image: directory '/'='/os/isodir'
xorriso : UPDATE :       7 files added in 1 seconds
ISO image produced: 187 sectors
Written to medium : 187 sectors at LBA 0
Writing to 'stdio:myos.iso' completed successfully.