The tsh shell should do each of the builtin commands without creating a child process:

• quit
• jobs
• fg
• bg

So eval should next call

        int builtin_cmd(char **argv)
     

passing the array of command line strings filled in by the parseline function.

• The builtin_cmd should determine if the command is one of the 4 built in commands and return 0 if it is not.

• Otherwise, the builtin_cmd should handle any of the 4 built in commands before returning and return 1.

You can use the strcmp function to check. E.g.

        if ( strcmp(argv[0], "quit") == 0 ) {
           exit(0);
        }...