options.addOption('f', "fileList", "a list of document files",
true, "FILE[,FILE...]", "Required (at least one of)");
options.addOption('d', "docFile",
"a file where each line is a document", true,
"FILE[,FILE...]", "Required (at least one of)");
options.addOption('R', "corpusReader",
"Specifies a CorpusReader which will " +
"automatically parse the document files that are " +
"not in the formats expected by -f and -d.",
true, "CLASSNAME,FILE[,FILE...]",
"Required (at least one of)");