git $Id$ how to ensure it is updated?

Question

In my repository I used the .gitattributes and append $Id$ hashes to my files. However in a typical commmit

$git commit -a -m ""
$git push origin master

I notice that the embedded $Id$ in the modified files dont change. A further

$git checkout modified_file.txt 

is necessary to ensure the updated $Id$.

Is there a command to update all the hashes automatically?

Answer 1

ident and other effects attributes work only on check-out. To force checkout remove .git/index and run git reset --hard .