asciidoctor/asciidoctor — pull request #152 by pilhuhn (2013-01-31 20:58:30+00:00)
Title: Print failed option args

When I do `asciidoc -b foo test.ad` , asciidoc prints "asciidoctor: FAILED: too many arguments" which is not helpful to the user especially as -b did expect one argument that is passed.

The patch explicitly tests if the argument matches expected values and prints a message otherwise.
If such errors show, processing is aborted.