       >  
,    ,       :

$ cat   > hold

cat: x: No such file or directory     (    )
$ cat hold
 .

,         
.       cat  
  tr (),       
. ,   cat   ,  
        ,  :

$ cat x  | tr "[-2][-]" "[-2][-]"

cat: x: No such file or directory     {    )
 .

        
  .  2>  ,   ;

  (   2).  1>  '
     (   1). 
   >:

$ cat   1> holdl 2> hold2
$ cat holdl

 .
$ cat hold2

cat: x: No such file or directory     (    )

    1>     
hold.   2>&1 ,    2   
 1.     ,    
 hold:

$ cat   1> hold 2>&1
$ cat hold

cat: x: No such file or directory     (    )
 .

   1> hold   2>&1.      
         , 
        hold,      hold 
    .

     2    
      1    tr:

$ cat x  2>&1 | tr "[a-zHa-]" "[-2][-]"

CAT: X: NO SUCH FILE OR DIRECTORY     (    )
 .

     1>&2     
 .         -
       echo.   
    echo    :

290                                       III.   Red Hat Linux