how to reboot from the other partiton by commond line

[jackysmith]

hi,everyone

there was one question confused me some days.
I want to reboot my mac from osx to other system . it can be done by press option key when reboot or setting the boot device in preferences . but in some reasons , i need to achive it by commond line.
but i don't know how to do
please give me some advices,thx

 

[einbahnstrasse]

Found this googling
sudo bless -mount "/Volumes/other disk" -setBoot

shutdown -r now

Where other disk is name of drive partition
I've done the shutdown command before the previous one supposed to change startup disk