My work requires us to have full-disk encryption, so these are the steps I use.
The basic idea is to create a LUKS-encrypted partition which is used as an LVM Physical Volume.
The GRUB boot partition isn't encrypted, but everything else is.
These steps tested and working on 22.04 (jammy) and 20.04 (focal).
| -- You need to create a Keychain item whose name matches what you use in place | |
| -- of "[keychain_item_name]" on line #7 (and whose password is identical to your | |
| -- user account's password). | |
| tell application "System Events" | |
| if ((get name of every process) contains "ScreenSaverEngine") then | |
| set pw to (do shell script "security find-generic-password -l \"[keychain_item_name]\" -w") | |
| tell application "ScreenSaverEngine" to quit | |
| delay 0.5 | |
| keystroke pw |