from: https://theantlrguy.atlassian.net/wiki/display/ANTLR4/ANTLR+Tool+Command+Line+Options
$ antlr4
ANTLR Parser Generator Version 4.0b3
-o <arg> specify output directory where all output is generated
-lib <arg> specify location of grammars, tokens files
-atn generate rule augmented transition network diagrams
-encoding <arg> specify grammar file encoding; e.g., euc-jp
-message-format <arg> specify output style for messages in antlr, gnu, vs2005