sed in-place – find and replace string in all files

Sed is a really powerful and useful linux program when you want to replace certain string in a file.
But it gets harder when you wan replase srting in all available files in directory .
Here is the solution with sed in-place command:

find /home/user/mydir -type f -exec sed -i 's/oldstring/newstring/g' {} \;

Useful links:

http://linux.about.com/od/commands/l/blcmdl1_sed.htm

Source:

http://www.brunolinux.com/02-The_Terminal/Find_and%20Replace_with_Sed.html