I am thinking   how   can I replace  a portion   of  a   file -- let's  say  lines  from  m  to n   with   lines  from   other   file  and  do this  in an  nice  manner.I  however don't   want to  use   editors , because  this  part will   be  a  small  part in something   bigger.
Replacing rows from one file with rows from other file
text processing;scripting;replace