Restore a file's modification time in Git

Question

I understand the default Git behaviour of updating the modification time every time it changes a file, but there are times when I want to restore a file's original modification time.

Is there a way I can tell Git to do this?

(As an example, when working on a large project, I made some changes to configure.ac, found out that autotools doesn't work on my system, and wanted to restore configure.ac's to its original contents and modification time so that make doesn't try to update configure with my broken autotools.)

Answer 1

Restore the modificaton time of a list of files to the author date of the their last commit with

gitmtim(){ local f;for f;do touch -d @0`git log --pretty=%at -n1 -- "$f"` "$f"; done;}; gitmtim configure.ac

It will not change directories recursively, though.

If you want to change a whole working tree, e.g. after a fresh clone or checkout, you may try

git log --pretty=%at --name-status --reverse | perl -ane '($x,$f)=@F;next if !$x;$t=$x,next if !defined($f)||$s{$f};$s{$f}=utime($t,$t,$f),next if $x=~/[AM]/;'

NB: I grepped for utime in builtin/clone.c and got no matches.