$ Is

bothfiles

filel

file2

  
 

 $ (name) (  $name,      ) -
    name (.  "$(...)   "
 9).   name     ,   -
 $(name}   .     -
       :

    .

        .

    .

     ,     .

:-     

 : -        -
  ,      :

${:-}

   : -  : "   
 ,        -
;     ".     -
  ,    LIT;   LIT    -
,     /home/alex/literature:

$ Is ${LIT:-/home/alex/literature}

        
:

$ Is ${LIT:-$HOME/literature}

         -
,      ,  :

$ Is ${LIT-$HOME/literature}

:=     

 :-    .    
         . 
   :=:

$(:=]

898                                                  VI. 