sed: Find pattern over two lines, not replace after that pattern

Question

Wow, this one has really got me. Gonna need some tricky sed skill here I think. Here is the output value of command text I\'m trying to replace:

...
fast
              


        

Answer 1

This might work for you:

sed '$!N;s/^fast\n\s*n :/Noun\n :/;P;D' file
...
Noun
 : abstaining from food