GRUB

Commands	What it does
sed -i 's/^GRUB_CMDLINE_LINUX_DEFAULT="/&option /' /etc/default/grub	adds kernel option to GRUB file

Replace &option with the kernel param like quiet or similar.

You will need to run this command when making changes to GRUB's file before rebooting

sudo update-grub

Editing the /etc/default/grub file and changing the GRUB_DEFAULT line to match this will boot the previous kernel as the default:

GRUB_DEFAULT="1>3"

Run the update-grub command to save that change.

fwupd

Commands	What it does
fwupdmgr get-devices	List devices supported by fwupd
fwupdmgr get-updates	Perform updates to devices supported by fwupd

Commands	What it does
apt policy packagename	Package information
apt-cache madison packagename	List available versions for a package
sudo apt install packagename –dry-run	See what packages will be installed with the package
apt policy packagename	Find version installed and available
sudo dpkg –remove –force-remove-reinstreq package_name	Remove broken package
sudo apt-mark hold packagename	Hold a package to the current version
dpkg –list	grep linux-image
apt list –installed	grep packagename

Commands	What it does
sudo update-initramfs -c -k kernelversion	Generate a new initramfs image with version

Commands	What it does
flatpak update	Update flatpak packages
flatpak list	Show the installed flatpak packages
flatpak search	Search flatpak packages from sources
flatpak remotes	List Flatpak remotes (other servers)

Commands	What it does
kioclient exec path/to/desktop/file	Runs the .desktop file

Commands	What it does
gsettings set org.gnome.desktop.interface scaling-factor 2	Change scaling for the UI
gsettings set com.ubuntu.user-interface.desktop cursor-size 48	Enlarge cursor
gsettings set org.gnome.desktop.background picture-uri 'file://PathToImage'	Change wallpaper
gsettings set org.gnome.desktop.wm.preferences button-layout "appmenu:minimize,maximize,close"	Enable Minimize and Maximize buttons