I'm trying to find a multiline pattern within a file and either add 2 line after it or replace it.

This is what the input and output should look like.

**INPUT**

```
$ DATE: Fri Apr 20 16:36:56 2012
$---------------------------$
$ FILE MANAGEMENT SECTION   $
$---------------------------$
$
$---------------------------$
$ EXECUTIVE CONTROL SECTION $
$---------------------------$

```

**OUTPUT**

```
$ DATE: Fri Apr 20 16:36:56 2012
$---------------------------$
$ FILE MANAGEMENT SECTION   $
$---------------------------$
$
BLKABLA
$
$---------------------------$
$ EXECUTIVE CONTROL SECTION $
$---------------------------$

```

Thanks