  Bourne Shell,  bash    Bourne Shell, -
  bash   ,   Bourne Shell. 
Bourne Shell  sh.   Linux sh     bash,
    ,   Bourne Shell.

  V UNIX   Korn Shell (ksh),   -
 (David Korn).      Bourne Shell  
  .   Bourne Again Shell, ,
     ,   
,    Shell.

  POSIX     -
  (POSIX 1003.2). Bourne Again Shell  , -
   POSIX.      -
 Bourne Again Shell   POSIX.     bash  
--posix,    Bourne Again Shell    
 POSIX.

   

       ,   -
         .

 

      .    
      "  "    . -
       :

=

       (=) .  -
     ,      -
    .

        , 
         : ${ }. 
   ,      ,  
 .  ,  Bourne Again Shell     -
          -
: $1, $2, $3  ..  $9.         ,
   , , ${10).   
  $0.

 ,   ,       -
     unset (   
.   " "  7):

$ unset PREF SUFF

Bourne Again Shell       -
 .          

282                                        III.   Red Hat Linux