'cat': function (tokens, pipes, exit) {
    var out = new view.bridge(pipes.viewOut);
    var chunkSize = 4096;

    // "cat <file> [file ...]" syntax.
    if (tokens.length < 2) {
      out.print('Usage: cat <file> [file] ...');
      return exit(false);
    }
    if (tokens.length > 2) {
      out.print('Multiple input files not supported yet.');
      return exit(false);
    }

    var errors = 0,
        track = whenDone(function () {
          exit(errors == 0);
        });

    for (i in tokens) if (i > 0) (function (file) {
      fs.stat(file, track(function (err, stats) {
        if (err) {
          errors++;
          out.print("No such file (" + file + ")");
          return;
        }
        fs.open(file, 'r', track(function (err, fd) {
          if (err) {
            errors++;
            out.print("Unable to open file (" + file + ")");
            return;
          }

          var position = 0, buffer = new Buffer(chunkSize);

          (function read() {
            fs.read(fd, buffer, 0, chunkSize, position, track(function (err, bytesRead) {
              if (err) {
                errors++;
                out.print("Error reading file (" + file + ")");
                return;
              }

              if (position == 0) {
                var headers = new meta.headers();
                headers.set({
                  'Content-Type': meta.sniff(file, buffer),
                  'Content-Length': stats.size,
                  'Content-Disposition': [
                    [ 'attachment' ],
                    [ 'filename', file ],
                  ],
                });

                pipes.dataOut.write(headers.generate());
              }

              pipes.dataOut.write(buffer.slice(0, bytesRead));
              position += bytesRead;

              if (position < stats.size) {
                read();
              }
            }));
          })();
        }));
      }));
    })(tokens[i]);


  },