nameFromFilename(filename) {
    this._name = path.basename(filename, path.extname(filename));

    return this;
  }
Set the name of the command from script filename, such as process.argv[1],
or require.main.filename, or __filename.

(Used internally and public although not documented in README.)

@example
program.nameFromFilename(require.main.filename);

@param {string} filename
@return {Command}