 cat,   less,    ,    out2
       :

$ cat out2

if [ $# -eq 0 ]
then

echo ": out2 [-v]  " 1>&2
exit 1
fi

if [ "$1" = "-v" ]
then

shift
 less "$@"
else

exec cat  "$@"
fi

        -
 ,      .    
        infile:

 < infile

,       -
   outfile  errfile:

 > outfile 2> errfile

         , 
       .   -
   ,      
.       -
 ,       . 
        
    /dev/tty.    -
 ,      ,  
.       , 
  .4       /dev/tty, 
     ,   , 
     .   
    ,    :

 > /dev/tty

        /dev/tty 
 :      ,   -
    .       
   ,     echo,
  :

echo -n "  : " > /dev/tty

   (   /dev/)    
  who am i.  tty      
.

902                                                  VI. 