How to retrieve the last modification date of all files in a Git repository

A simple answer would be to iterate through each file and display its modification time, i.e.:

git ls-tree -r --name-only HEAD | while read filename; do
  echo "$(git log -1 --format="%ad" -- $filename) $filename"
done

This will yield output like so:

Fri Dec 23 19:01:01 2011 +0000 Config
Fri Dec 23 19:01:01 2011 +0000 Makefile

Obviously, you can control this since its just a bash script at this point--so feel free to customize to your heart's content!

This approach also works with filenames that contain spaces:

git ls-files -z | xargs -0 -n1 -I{} -- git log -1 --format="%ai {}" {}

Example output:

2015-11-03 10:51:16 -0500 .gitignore
2016-03-30 11:50:05 -0400 .htaccess
2015-02-18 12:20:26 -0500 .travis.yml
2016-04-29 09:19:24 +0800 2016-01-13-Atlanta.md
2016-04-29 09:29:10 +0800 2016-03-03-Elmherst.md
2016-04-29 09:41:20 +0800 2016-03-03-Milford.md
2016-04-29 08:15:19 +0800 2016-03-06-Clayton.md
2016-04-29 01:20:01 +0800 2016-03-14-Richmond.md
2016-04-29 09:49:06 +0800 3/8/2016-Clayton.md
2015-08-26 16:19:56 -0400 404.htm
2016-03-31 11:54:19 -0400 _algorithms/acls-bradycardia-algorithm.htm
2015-12-23 17:03:51 -0500 _algorithms/acls-pulseless-arrest-algorithm-asystole.htm
2016-04-11 15:00:42 -0400 _algorithms/acls-pulseless-arrest-algorithm-pea.htm
2016-03-31 11:54:19 -0400 _algorithms/acls-secondary-survey.htm
2016-03-31 11:54:19 -0400 _algorithms/acls-suspected-stroke-algorithm.htm
2016-03-31 11:54:19 -0400 _algorithms/acls-tachycardia-algorithm-stable.htm
...

The output can be sorted by modification timestamp by adding | sort to the end:

git ls-files -z | xargs -0 -n1 -I{} -- git log -1 --format="%ai {}" {} | sort

This is a small tweak of Andrew M.'s answer. (I was unable to comment on his answer.)

Wrap the first $filename in double quotes, in order to support filenames with embedded spaces.

git ls-tree -r --name-only HEAD | while read filename; do
    echo "$(git log -1 --format="%ad" -- "$filename") $filename"
done

Sample output:

Tue Jun 21 11:38:43 2016 -0600 subdir/this is a filename with spaces.txt

I appreciate that Andrew's solution (based on ls-tree) works with bare repositories! (This isn't true of solutions using ls-files.)