Arg! my comment seems to have gotten lost.  There was a big comment here... you should use $this->options_string() for formatted the argumetns, also surround beginning text here in __FORMAT_TEXT__.  All of that will align args and format for the width of the terminal things are being run in.  See grep.pm for an example that isn't too hard.

Also maybe spruce up the --begin and --end descriptions, maybe something like:

"Begins outputting records when this snippet is true.  If omitted, outputs starts from beginning of the stream.  See --help-snippet for details on snippets."