Using Workbench Command

IMPORT A GIFTI LABEL FILE FROM A METRIC FILE
   wb_command -metric-label-import
      <input> - the input metric file
      <label-list-file> - text file containing the values and names for labels
      <output> - output - the output gifti label file

      [-discard-others] - set any values not mentioned in the label list to the
         ??? label

      [-unlabeled-value] - set the value that will be interpreted as unlabeled
         <value> - the numeric value for unlabeled (default 0)

      [-column] - select a single column to import
         <column> - the column number or name

      [-drop-unused-labels] - remove any unused label values from the label
         table

      Creates a gifti label file from a metric file with label-like values.
      You may specify the empty string (use "") for <label-list-file>, which
      will be treated as if it is an empty file.  The label list file must have
      the following format (2 lines per label):

      <labelname>
      <key> <red> <green> <blue> <alpha>
      ...

      Label names are specified on a separate line from their value and color,
      in order to let label names contain spaces.  Whitespace is trimmed from
      both ends of the label name, but is kept if it is in the middle of a
      label.  Do not specify the "unlabeled" key in the file, it is assumed
      that 0 means not labeled unless -unlabeled-value is specified.  The value
      of <key> specifies what value in the imported file should be used as this
      label.  The values of <red>, <green>, <blue> and <alpha> must be integers
      from 0 to 255, and will specify the color the label is drawn as (alpha of
      255 means fully opaque, which is probably what you want).

      By default, it will create new label names with names like LABEL_5 for
      any values encountered that are not mentioned in the list file, specify
      -discard-others to instead set these values to the "unlabeled" key.