How to run "gg=G" on several files?

Question

In vim, gg=G does a great job re-indenting your current file and I'd like to do that on several files.

I would like to do something like this:

files=`find $1 -type f`
for file in $files
do
    vim -e -s -n "+gg=G|wq" $file
done

The problem is that gg=G is not a command (if you type :gg=G in vim, it throws an error), so it doesn't work...

Answer 1

I think I found it! (of course 10 minutes after I posted the question, even though I searched before for 4 hours)

files=`find $1 -type f`
for file in $files
do
    vim -e -s -n "+normal gg=GZZ" $file
done

Answer 2

Open the files you want to modify in vim

vim *

Then use :bufdo to execute a command in all loaded buffers

:bufdo normal 0=G

Finally, save all files and exit

:wqa