sed insert lines before/after pattern match

Yet another wicked cool sed trick that I accomplished recently after a pile of googling. I needed to add a couple of lines of code into several files that all had great markers already in the code where I needed the new lines. I just had to do a pattern match on the marker phrases, and add the lines either before or after as needed. Looked like a job for sed (although some pointed out in the forum threads that I googled that awk would work probably easier). Anyhow, here's what I did to add a line after:

find . -name "prefix*.c" -exec sed -e '/pattern1/G;a\{new line1' -e'}' {} \;

I got the "G" part from examples and never did verify its offical capabilities, but that's what adds an extra blank line (from man, it seems to be appending the swap line to the current line?). The two -e arguments are the key to overcoming the difficulties with the "a" command.

In the spots where I wanted to add the line before a particular line, I didn't have time to figure out how to make a single command that would add the extra line plus a blank line, so I just wimped out and used two commands. The "x;p;x" bit is from another example in the single-liner file:

find . -name "prefix*.c" -exec sed -e '/pattern2/i\{new line2' -e'}' {} \;

find . -name "prefix*.c" -exec sed -e '/pattern2/{x;p;x;}' {} \;