Question : File manipulation SED or AWK

I'm trying to create a .ksh file in UNIX that will append a new line to the line ABOVE the line it finds.  So, the unique charactaristic would exist on the "portalinstance" node below.  I want to find that lina and then drop another "component" BEFORE the "component" line above it.

         


I need to use a script to accomplish this and have little experience with SED and AWK.

Thanks.

Answer : File manipulation SED or AWK

Thanks for the suggestions.  I ended up using an "ed" script.  It turned out to be rather easy.  I built a list of commands in the script and then input them into ed:
ed <

input file:
/
^
i

.
/
+
a

.
w
q