Q:

Delete a previously added rule in ufw

I created a firewall rule for an application and put into /etc/ufw/applications.d, added that rule with command
sudo ufw allow MyApp

but now I cannot delete it. When I do
sudo ufw delete MyApp

it just prints the list of available commands like my command was invalid, which is what it probably was, but I don't know any other ways.

A:

If you just want to delete the rule, the syntax is 
sudo ufw delete allow MyApp

see: https://help.ubuntu.com/community/UFW

