s2disk is a program that will save the state of the whole system to disk and power off your system. After restarting your system it will be put back in the exact system state you left it (this is sometimes called hibernation).

s2both will do precisly the same as s2disk except that it will not power off the system, but will suspend it to ram (put the system in S3 mode). This has the advantage that resume will be faster, with the disadvantage that you still use batteries. If they batteries do deplete, you still have the system state saved to disk and can resume without data loss. The s2both command also inherits all command line arguments from s2ram.

You will need to set up an initramfs which calls the resume program for this to work. If you use a package distributed with your Linux distribution, the kernel package which was made with the --initrd option and you use mkinitramfs-tools, this package should include the necessary parts on your initramfs.

The uswsusp system supports encrypting the image written to disk and features a splash system, see uswsusp.conf(5) for more information.