Convert git date using GNU date

Question

I would like to convert the git date into the format of Ymd. Here's my attempt:

$>>git log -1 --format="%cd" | xargs date Y%m%d

But this returns this error:

date: extra operand ‘Thu’
Try 'date --help' for more information.

Any ideas how to convert git date like this:

Thu Sep 19 17:03:12 2013 +0100

To something like this:

20130919

Thanks.

Answer 1

It'd be easier if you make git emit the UNIX timestamp. Say:

git log -1 --format="%at" | xargs -I{} date -d @{} +%Y%m%d

From the documentation:

%at: author date, UNIX timestamp

Answer 2

Instead of using %cd, use %ct which would get the timestamp:

git log -1 --format="%ct" | xargs -i --  date -d '@{}' '+%Y%m%d'