Insert multiple lines of text before specific line using Bash

Question

I am trying to insert a few lines of text before a specific line, but keep getting sed errors when I try to add a new line character. My command looks like:

Answer 1

When the lines to be inserted are the result of some command "mycmd" (like cat results.txt or printf "%s\n" line{1..3}), you can do

sed -i 's/Line to insert after/r' <(cmd) file
or 
sed -i 's/Line to insert after/echo "&";cmd/e' file

The last command can be simple modified when you want to insert before some match.