 .  . 7.1     Is: -r  -.   
         -
 .        :

 Is -xr    ,    Is -rx.    
  Is - -.

    .  ,  
,     .       -
,         ,  
    .   df,    
,     (, ,   ).  
 Used ()  Avail ().    df -h 
df --human-readible.  ?     ,
  ,     Is   -1.

  

      tty  Linux ( 
  Linux)     ,  
 -  .   <CONTROL+H> ( )
 <CONTROL+U> ( )     -
   :       
.        <CONTROL+W>
( ).      ,  
        .   RETURN
       .

           -
 (parse)     (. 7.2).   
 . '        -
  ( ),       
      (TAB  )     -
 .   ( )      
   ,   . ,  Is  
   :

$ Is


$ /bin/Is

'   ,         .
     :

$ >bb < aa cat

     (.  ""  
 ),            , 
    ,   .  
,     ,  .

224                                               II.   Red Hat Linux