     () ,   ,
   (      . 28.6).
        , 
.      (&),   
         RETURN  -
 ,   .      -
  ,       . 
      :  -
   ,    .

   .     -
,   ;      -
  unset.     ,   -
         -
 export.       . 
   ,    9.7, 
        .    
,    .

 9.7.    

/    


CDPATH          ,      -
 cd.

HISTFILE        ,        .
HISTFILESIZE     ,   HISTFILE (. . 9.3).

HISTSIZE        ,     ( , -
    ) (. . 9.3).

HOME              .

IFS               .

MAIL            ,       .

MAILCHECK       ( )       
 .

MAILPATH           .

PATH              .

PS1               1.

PS2               2.

$0              .

$               -    (    set).

$*                  (    set).

$@                  (    set).

$#                 .

$$              PID  .

$!              PID   .

$?                 ,  .

 9.  II: Bourne Again Shell                                            345