perl, 61 bytes

Result

AC

Duration

709ms

Code [DL]

$_=`dd`;/T/;s/(\n.{$-[0]}) /\1T/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                           
                      T                           
                      T                           
                      T                           
                      T                           
                      T                           
                      T                           
                      T                           
                      T                           
           KKKKKKKKKKKT                           

stderr

2+1 records in
2+1 records out

strace