code: public static String execCommand(Map<String,String> env, String ... cmd)
          throws IOException {
          return execCommand(env, cmd, 0L);
      }
docs: Static method to execute a shell command. Covers most of the simple cases without requiring the user to implement the <code>Shell</code> interface.
  
  @param env the map of environment key=value
  @param cmd shell command to execute.
  @return the output of the executed command.