When I use the command
sudo systemctl hibernate, the system seems to go to hibernation, but when restarted, it is a fresh start without any of the previous windows that were left open.
And when I tried
sudo pm-hibernate it says
sudo: pm-hibernate: command not found.
Here is my drive configuration if that helps:
/dev/sda = SSD with Windows 10 only (Windows C drive and the reserved partition).
/dev/sdb = HDD with NTFS and EXT4 partitions containing regular data only, no OS here currently.
/dev/sdc = SSD (GPT partition) with Ubuntu 18.04 (/ partition), swap area and a shared NTFS game drive.
GRUB is installed on /dev/sda.
I created a new parition table on /dev/sdc using msdos instead of GPT. Then I reinstalled Ubuntu and installed GRUB on /dev/sdc. After these changes,
sudo hibernate seems to be working.
sudo hibernate seems to go to hibernation without locking the screen (i.e. anyone could turn on the PC and automatically be logged in), I added this line to
/etc/sudoers (cln is my username):
cln ALL=NOPASSWD: /usr/sbin/hibernate
and made this executable script:
#!/bin/bash xdg-screensaver lock sudo hibernate
Now I am able to just double-click on this script, select Run, and directly go to hibernation while also locking the screen. Much more comfortable.