perl, 58 bytes

Result

AC

Duration

773ms

Code [DL]

$_=`dd`;/T/;s/\n.{$-[0]}\K/T/g;s/K */K x length$&/ge;print

stdin

             T                                    
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
 K                                                

stdout

             T                                    
             T                                     
             T                                     
             T                                     
             T                                     
             T                                     
             T                                     
             T                                     
             T                                     
             T                                     
             T                                     
             T                                     
             T                                     
             T                                     
 KKKKKKKKKKKKT                                     

stderr

1+1 records in
1+1 records out

strace