Linux disable and reenable laptop keyboard

xinput -list

Note the id of “AT Translated Set 2 keyboard” (14 in my case), it’s the laptop keyboard, and of the one labeled “master keyboard” (3 in my case). xinput float $id and xinput float $id $id-master. ¹

xinput float 14         #disables laptop keyboard
xinput reattach 14 3    #enables it back

ssh keys (id_rsa, id_rsa.pub)

Errors like:

Permissions 0644 for '/home/me/.ssh/id_rsa' are too open.
It is required that your private key files are NOT accessible by others.
This private key will be ignored.

can be fixed by setting the permissions to 400.

Java complaining about --add_opens + $JAVACMD

For some reason the script took java8 instead of the java11 returned by which java, through $JAVACMD. Temporarily fixed by doing JAVACMD="/usr/bin/java" ./the_script.sh.