How to make a recursive replacement in a file?

Question

Let's say I want to scan every file in this directory (also recursive).

And I want to replace happy.magic with sad.apps.magic

How can i do this?

Answer 1

 find . -type f -exec sed -i 's,happy.magic,sad.apps.magic,g' {} \; 

Answer 2

Eric is right, but just to be clear:

 find ./ -type f -exec sed -i "s/happy\.magic/sad\.apps\.magic/g" {} \;