usage: catw {OPTIONS} [FILES...] -o OUTFILE

  If FILES is "-", read from stdin.
  If there is no OUTFILE, write to stdout and exit without watching.

  OPTIONS:

    -w, --watch      Watch for changes.
                     Default: true except when writing to stdout.
 
    -c, --command    Execute a transform command for file before concatenating.
                     The env var $FILE will be set for each file path.
 
    -t, --transform  Transform each file using a module.

    -v, --verbose    Print the number of bytes written whenever a file changes.

    -h, --help       Print this help message.

Make sure to escape the globs that you want `catw` to watch so your shell won't
expand them.