Manually suspend and hibernate

The /sys/power/state file controls system sleep states.
The /sys/power/disk file controls the method to hibernate to disk.

Reading the files returns the available options:

[root@archlinux ~]# cat /sys/power/state
freeze mem disk
[root@archlinux ~]# cat /sys/power/disk
[platform] shutdown reboot suspend
[root@archlinux ~]#

If I want to suspend to memory I need to do:

[root@archlinux ~]# echo mem > /sys/power/state

Suspend to disk:

[root@archlinux ~]# echo disk > /sys/power/state

The suspend-to-disk method may be chosen by writing to /sys/power/disk one of the accepted strings: