How to copy just timestamps, or “I should have used cp -p”

Question

I foolishly copied a very large amount of data using cp -r.

Looking at it now, I've realized that this means I lost my file modification times. I should have used cp -rp.

My directory structure and files haven't changed: is there any way to copy over just the attributes/timestamps now? I'm thinking rsync might be useful.

Answer 1

This worked well for me:

rsync -vrt --size-only /src /dest

The --size-only command compares files only based on size, which was largely unchanged for me. The -t copies over the timestamps.

Answer 2

You can do this with find and touch.

cd destination
find -depth -exec touch -r /path/to/source/{} {} \;

The -depth option arranges for directories' times to be set after their contents have been set. This assumes that your find interpolates {} when it's a substring of an argument. If it doesn't, invoke a shell:

find -depth -exec sh -c 'for x; do touch -r "$0/$x" "$x"' /path/to/source {} +

To copy the access times as well, run touch -a … as well.

find -depth -exec touch -a -r /path/to/source/{} {} \; -exec touch -r /path/to/source/{} {} \;