change commit date code example

Example 1: git change git commit date

Set GIT_COMMITTER_DATE="Wed Sep 23 9:40 2015 +0200" git commit --amend --date "Wed Sep 23 9:40 2015 +0200"

Example 2: github change commit date

git filter-branch --env-filter \
    'if [ $GIT_COMMIT = 119f9ecf58069b265ab22f1f97d2b648faf932e0 ]
     then
         export GIT_AUTHOR_DATE="Fri Jan 2 21:38:53 2009 -0800"
         export GIT_COMMITTER_DATE="Sat May 19 01:01:01 2007 -0700"
     fi'