I have two files, one with blocks like<record>line1line2line3#model bla bla bla</record>while the other file has exactly the same number of  blocks, but without the hashtag comments, ie like<record>line4line5line7line8line9line10</record>So, what I want to do, is to copy from the 1st  block of the first file the hashtag to the 1st block of the second file so that my other file also looks like<record>line4line5line7line8line9line10#model bla bla bla</record>
Copying hashtag comments recursively within 
replace