code: function bin(argv) {
    if (!argv[2]) {
      console.error("url is required")
      console.error("Usage : cat <url>")
      process.exit(-1)
    }
    shell.cat(argv[2], function(err, res, uri) {
      if (err) {
        console.error(err)
      } else {
        console.log(res)
      }
    })
  }
docs: cat as a command
  @param  {Array} argv Args, argv[2] is the uri