DebianAlternatives

Each alternative has a priority associated with it. When a link group is in automatic mode, the alternatives pointed to by members of the group will be those which have the highest priority.

update-alternatives --list x-www-browser
update-alternatives --query x-www-browser

update-alternatives --install /usr/bin/x-www-browser x-www-browser /var/lib/flatpak/exports/bin/org.mozilla.firefox 200
update-alternatives --set x-www-browser /var/lib/flatpak/exports/bin/org.mozilla.firefox

• https://wiki.debian.org/DebianAlternatives
• https://manpages.debian.org/stretch/dpkg/update-alternatives.1.en.html

Reset root password

To reset a lost root password on a Debian/Ubuntu machines:

In Grub edit (e) the default entry (“Debian GNU/Linux” or similar) and add init=/bin/bash at the end of the linux line, then Ctrl + x to boot, then:

mount -o remount /
passwd

US Keyboard layout for = :