Find and replace on windows

You can run a command on all windows in the current collection with :windo

To do a find and replace on the current set of windows do:
:windo %s/foo/bar
This will replace foo with bar in each file.

:windo %s/;$//
This will remove semicolons at the end of lines in javascript.

Alternatively (not pictured in the above gif) you can run a macro on each open by using :windo execute "normal @a" | update - to run macro @ and save after file change.

Further Reading

:h :windo :h :bufdo :h :tabdo :h :argdo

More Gifs