Syntax checking of keymap.rb

If your keymap.rb doesn't make your keyboard run, you likely have mistyped in the keymap.rb.

Syntax checker of Ruby will help you.

On the command line (Be sure to insert -c option):

ruby -c path/to/keymap.rb

If the command above prints Syntax OK, your keymap.rb basically doesn't have any mistake in terms of Ruby syntax (Note that it doesn't mean there are no mistakes of any kind).

Otherwise, that command reports a syntax error that you have to fix.

If you don't have a ruby command, install one according to https://www.ruby-lang.org/en/documentation/installation/