gml2gv: option -- unrecognized
Usage: gml2gv [-v?] [-g<name>] [-o<file>] <files>
  -g<name>  : use <name> as template for graph names
  -v        : verbose mode
  -o<file>  : output to <file> (stdout)
  -?        : print usage
If no files are specified, stdin is used