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Initial Shell Code - do_bgfg

    1   /* 
    2    * do_bgfg - Execute the builtin bg and fg commands
    3    */
    4   void do_bgfg(char **argv) 
    5   {
    6       return;
    7   }

Example

tsh> jobs
[1] (31251) Stopped myspin 20
tsh>
   

The process executing the program "myspin" is stopped in the background.

It has process id (pid) 31251 and job id (jid) 1.

The shell is waiting for a new command while "myspin" is stopped.

The fg or the bg command will cause myspin to continue running.

The fg command will cause myspin to run as the foreground process - the shell will wait for it to finish.

The bg command will cause myspin to run, but still in the background - the shell will not wait, but will print the prompt to read another command while myspin runs.



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