code: void cat(String src, boolean verifyChecksum) throws IOException {
      //cat behavior in Linux
      //  [~/1207]$ ls ?.txt
      //  x.txt  z.txt
      //  [~/1207]$ cat x.txt y.txt z.txt
      //  xxx
      //  cat: y.txt: No such file or directory
      //  zzz
  
      Path srcPattern = new Path(src);
      new DelayedExceptionThrowing() {
        @Override
        void process(Path p, FileSystem srcFs) throws IOException {
          if (srcFs.getFileStatus(p).isDir()) {
            throw new IOException("Source must be a file.");
          }
          printToStdout(srcFs.open(p));
        }
      }.globAndProcess(srcPattern, getSrcFileSystem(srcPattern, verifyChecksum));
    }
docs: Fetch all files that match the file pattern <i>srcf</i> and display
  their content on stdout.
  @param srcf: a file pattern specifying source files
  @exception: IOException
  @see org.apache.hadoop.fs.FileSystem.globStatus