1   /* 
    2    * eval - Evaluate the command line that the user has just typed in
    3    * 
    4    * If the user has requested a built-in command (quit, jobs, bg or fg)
    5    * then execute it immediately. Otherwise, fork a child process and
    6    * run the job in the context of the child. If the job is running in
    7    * the foreground, wait for it to terminate and then return.  Note:
    8    * each child process must have a unique process group ID. Otherwise,
    9    * all children of the shell including background children would be
   10    * in the same process group and would receive a SIGINT (SIGTSTP) signal
   11    * when we type ctrl-c (ctrl-z) at the keyboard. Only the foreground process
   12    * group should receive those signals.
   13   */
   14   void eval(char *cmdline) 
   15   {
   16       return;
   17   }