ast_comparator/test/student_data/handout/shlab-handout/cases/51_tsh.c
/*
 * builtin_cmd - If the user has typed a built-in command then execute
 *    it immediately.
 */
If the user has typed a built-in command then execute
it immediately.
If the user has typed a built - in command then execute it immediately .
int builtin_cmd(char **argv)
{
  if(argv[0] == NULL) 
    return 0;
  else {
    if(strcmp(argv[0], "quit") == 0) { 
      exit(0);
    }
    else if(strcmp(argv[0], "fg") == 0 || strcmp(argv[0], "bg") == 0) { 
      do_bgfg(argv);
      return 1;
    }
    else if(strcmp(argv[0], "jobs") == 0) { 
      listjobs(jobs);
      return 1;
    }
  }
  return 0;     
}
int builtin_cmd ( char * * argv ) { if ( argv [ 0 ] == NULL ) return 0 ; else { if ( strcmp ( argv [ 0 ] , " " ) == 0 ) { exit ( 0 ) ; } else if ( strcmp ( argv [ 0 ] , " " ) == 0 || strcmp ( argv [ 0 ] , " " ) == 0 ) { do_bgfg ( argv ) ; return 1 ; } else if ( strcmp ( argv [ 0 ] , " " ) == 0 ) { listjobs ( jobs ) ; return 1 ; } } return 0 ; }
builtin_cmd - If the user has typed a built-in command then execute
    it immediately.
builtin_cmd - If the user has typed a built - in command then execute it immediately .
// if argv is empty, return 0 // command quit: exit with signal 0 // command fg & bg: execute do_bgfg // command jobs: print the list of jobs /* not a builtin command */