Replace delimited block of text in file with the contents of another file

Question

I need to write a simple script to replace a block of text in a configuration file with the contents of another file.

Let\'s assume with have the following simplifie

Answer 1

How about this little snippet I created:

sed -n \
  -e "1,/<\!-- BEGIN realm -->/ p" \
  -e"/<\!-- END realm -->/,$ p" \
  -e "/<\!-- BEGIN realm -->/ r realm.xml" \
  server.xml

The first commands prints the lines up to the second command prints the line starting at and the third commands append the text in the file 'realm.xml'. If only I could simplify the removing of the lines between and without removing the marker lines it would as simple as it gets. And it can be done inplace with sed!!!