 set    ,   
.             set -
  .          ;

     .      
   . 9.2.

 9.2.   set
       

-a (allexport)         
 .

-f (noglob)      bash     (globbing).

- ()     bash    ,    .  
     ;   -
  .

-t (exit)           ,    .

-u (nounset)          .   
 , bash  ,    .
  ,      
  ;    
unbound variable ( )     .

 

      , 
       .  -
       ($)   
.      ,   
 .

$*  $@     

 $*     ,    
   display_all.  $@  $* ,  -
 ,      .  "$*"   -
 (     ),  "$@"  -
,        .  -
      $@  ,  $*  .
 whos   28.

$#     

      showargs    ,
 $#      .   -
   :

$ cat num_args

echo "   

 $# ."

$ num_args helen alex jenny

   
 3 .

 9.  II: Bourne Again Shell                                            319