Confusion Regarding --force option

I am accessing a CentOS 7 VM through Putty but I have had the issue on Ubuntu as well.

Highlight is awesome and very helpful.

The only issue I have run into is that I cannot for the life of me figure out how to set the default language when Highlight does not recognize the extension or there is no extension.

My normal command is usually highlight -O ansi

I am trying to get the --force[=syntax] option to work as it is specified in the documentation.

--force[=syntax] generate output if input syntax is unknown

I have tried the following with no success.

highlight -O ansi --force=sh

highlight -O ansi --force="sh"

highlight -O ansi --force"=sh"

highlight -O ansi --force-sh

highlight -O ansi --force sh

highlight -O ansi --force "sh"

highlight -O ansi --force "=sh"

highlight -O ansi --force ="sh"

I appreciate any help figuring out the correct way to format the command.