code: function updateOps() {
    let value = commandInput.value.replace('\t', ''); // get rid of tabs
    let argv = yargs
      .options(yargsOptions)
  		.parse(value);
  		
    let files = [];
    let newFileName = '';
    let operations = [];
    if (argv._.length > 1) {
      try {
        newFileName = path.parse(argv._.pop());
        files = rename.getFileArray(argv._);
        OPTS = rename.argvToOptions(argv);
        operations = rename.getOperations(files, newFileName, OPTS);
        OPS = operations;
      } catch (ex) {
        if (ex === 'InvalidReplacementVariable') {
          operations = [{text: 'Invalid replacement variable'}];
        } else {
          operations = [{text: 'Invalid command'}];
        }
      }
    }
    
    let content = operations.map(function(value) { return value.text; }).join('\n');
    opList.setContent(content);
  }
docs: ==========  HELPER FUNCTIONS  ==========