You can do an interactive rebase and choose edit for the commit whose date you would like to alter. When the rebase process stops for amending the commit you type in for instance:

git commit --amend --date="Wed Feb 16 14:00 2011 +0100" --no-edit

P.S. --date=now will use the current time.

Afterward, you continue your interactive rebase.

To change the commit date instead of the author date:

GIT_COMMITTER_DATE="Wed Feb 16 14:00 2011 +0100" git commit --amend --no-edit

The lines above set an environment variable GIT_COMMITTER_DATE which is used in amending commit.

Everything is tested in Git Bash.

Use git filter-branch with an env filter that sets GIT_AUTHOR_DATE and GIT_COMMITTER_DATE for the specific hash of the commit you're looking to fix.

This will invalidate that and all future hashes.

Example:

If you wanted to change the dates of commit 119f9ecf58069b265ab22f1f97d2b648faf932e0, you could do so with something like this:

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'

A better way to handle all of these suggestions in one command is

LC_ALL=C GIT_COMMITTER_DATE="$(date)" git commit --amend --no-edit --date "$(date)"

This will set the last commit's commit and author date to "right now."

I wrote a script and Homebrew package for this. Super easy to install, you can find it on GitHub PotatoLabs/git-redate page.

Syntax:

git redate -c 3

You just have to run git redate and you'll be able to edit all the dates in vim of the most recent 5 commits (there's also a -c option for how many commits you want to go back, it just defaults to 5). Let me know if you have any questions, comments, or suggestions!

How to Edit Multiple Commit Dates

Other answers aren't very convenient for editing several commit dates. I've come back to this question after a few years to share a technique.

To change the dates of the last 4 commits:

git rebase -i HEAD~4

Edit the rebase as follows, inserting exec lines to modify dates as needed:

pick 4ca564e Do something
exec git commit --amend --no-edit --date "1 Oct 2019 12:00:00 PDT"
pick 1670583 Add another thing
exec git commit --amend --no-edit --date "2 Oct 2019 12:00:00 PDT"
pick b54021c Add some tests
exec git commit --amend --no-edit --date "3 Oct 2019 12:00:00 PDT"
pick e8f6653 Fix the broken thing
exec git commit --amend --no-edit --date "4 Oct 2019 12:00:00 PDT"

Update (Sep. 2021):

If you want to see the original commit date in the rebase instruction list (Git 2.6+):

git config --add rebase.instructionFormat "[%ai] %s"

Then you'll see something like

pick 4f5a371f [2021-09-08 02:56:50 -0700] Add npm events
pick 67937227 [2021-09-09 03:05:42 -0700] Fixup

After reading all the answers I came up with a more succinct and convenient way of editing the date of multiple commits at once without the need of rebasing interactively:

git rebase HEAD~4 --exec "git commit --amend --no-edit --date 'now'"

It changes both the committer and author dates.

I created this npm package to change date of old commits.

https://github.com/bitriddler/git-change-date

Sample Usage:

npm install -g git-change-date
cd [your-directory]
git-change-date

You will be prompted to choose the commit you want to modify then to enter the new date.

If you want to change a commit by specific hash run this git-change-date --hash=[hash]

The most simple way to modify the date and time of the last commit

git commit --amend --date="12/31/2021 @ 14:00"

If commit not yet pushed then I can use something like that:

git commit --amend --date=" Wed Mar 25 10:05:44 2020 +0300"

after that git bash opens editor with the already applied date so you need just to save it by typing in the VI editor command mode ":wq" and you can push it

Set the date of the last commit to the current date

GIT_COMMITTER_DATE="$(date)" git commit --amend --no-edit --date "$(date)"

Set the date of the last commit to an arbitrary date

GIT_COMMITTER_DATE="Mon 20 Aug 2018 20:19:19 BST" git commit --amend --no-edit --date "Mon 20 Aug 2018 20:19:19 BST"

Set the date of an arbitrary commit to an arbitrary or current date

Rebase to before said commit and stop for amendment:

1. git rebase <commit-hash>^ -i
2. Replace pick with e (edit) on the line with that commit (the first one)
3. quit the editor (ESC followed by :wq in VIM)
4. Either:

• GIT_COMMITTER_DATE="$(date)" git commit --amend --no-edit --date "$(date)"
• GIT_COMMITTER_DATE="Mon 20 Aug 2018 20:19:19 BST" git commit --amend --no-edit --date "Mon 20 Aug 2018 20:19:19 BST"

Source: https://codewithhugo.com/change-the-date-of-a-git-commit/

For those using Powershell

git rebase DESIRED_REF^ -i

$commitDateString = "2020-01-22T22:22:22"
$env:GIT_COMMITTER_DATE = $commitDateString
git commit --amend --date $commitDateString
$env:GIT_COMMITTER_DATE = ""

git rebase --continue

Credit to https://mnaoumov.wordpress.com/2012/09/23/git-change-date-of-commit/

Edit the author date and the commit date of the last 3 commits:

git rebase -i HEAD~3 --committer-date-is-author-date --exec "git commit --amend --no-edit --date=now"

The --exec command is appended after each line in the rebase and you can choose the author date with the --date=..., the committer date will be the same of author date.

Information from July 2022:

This one working amazing with current timestamp:

git commit --amend --date=now --no-edit

And this one - with any date format:

git commit --amend --date="Mon Jul 25 10:37:36 2022 +0300" --no-edit

I wanted to make sure that I update my code’s copyright comments at precisely midnight, and I didn’t want to risk a tiny delay with at or cron. So, I commited the code and then:

GIT_COMMITTER_DATE="Fri Jan 1 00:00:00 2021 +1000" git commit --amend --no-edit --date="Fri Jan 1 00:00:00 2021 +1000"

(Or perhaps even set the UTC offset to 0? Decisions… ) Now I can push!

Happy new year, everybody

For updating the date of the 5 last commits to the current date (this method doesn't allow to update the initial commit):

git rebase HEAD~5 --exec "git commit --amend --no-edit --date 'now'"

For all commits after commit 95f5074…15074db2:

git rebase 95f5074…15074db2 --exec "git commit --amend --no-edit --date 'now'"

For all commits (including the initial commit):

git rebase --root --exec "git commit --amend --no-edit --date 'now'"

Add -i for the interactive mode.

Run git log --format=fuller --show-signature to validate the changes.

Run git push -f to update the remote repository (⚠️Danger zone)

There are implications. For instance:

• Commit IDs will change, so you will have to recreate tags
• You will lose original signatures
• This will use your .gitconfig, this means your key will be used for signing commits (if Git is configured to sign commits)

TL;DR: Matching dates + re-creating GPG signatures

^{(Comment/edit if you know a workaround for the stripping to preserve the original signature.)}

I'll bump this old thread because a feature of signing commits has been introduced and all of these git filter-branch and likes basically strip the signatures as specified in the docs:

... If the tag has a signature attached, the signature will be stripped. It is by definition impossible to preserve signatures. ... (source: --tag-name-filter )

But it'll also break the pretty Verified badge on a GitHub commit (and in other Git hosting places if implemented in the same way), so this will fix that as well. Partially.

Afaik it's not possible to mangle a (GPG) signature through git command in a way that it also contains the date of a commit instead of the date of signing in a simple way and therefore even if the dates for authoring and commit are moved, it'll still be the present date, example:

commit <hash>
gpg: Signature made Sun 25 Jul 2021 00:00:00 PM TZ
gpg:                using TYPE key KEY
gpg: Good signature from "Signer <email@domain.tld>"
Author:     Author <email@domain.tld>
AuthorDate: Sat Jan 1 00:00:00 2000 +0000
Commit:     Author <email@domain.tld>
CommitDate: Sat Jan 1 00:00:00 2000 +0000

So imagine you have a repo you want to sign from a certain commit (I'll go for the root commit; not recommended if somebody else works on the repo). The documentation for git commit says it pulls data from env vars too, if present, thus we have a place to put the input to.

To retrieve the data (can be set with git commit --date=...) we can take a look at git show --format=%ad, so for a raw date string that would be:

git show --format=%ad --no-patch
# Sat Jan 1 00:00:00 2000 +0000

So we have:

• point of start
• raw date string for each commit
• GIT_COMMITTER_DATE to match the dates (author -> committer)

For rebasing let's do this:

git rebase --root <branch-name> --keep-empty --interactive

which will go for the root commit of a branch <branch-name>, preserve any empty commits created with git commit -m "empty" --allow-empty and ask you which commits to modify. There you change the desired commits from pick to edit (for my case that'd be marking all of them as edit), then you'll be dropped into a detached HEAD commit and from here the fun begins.

# or "while :"
while true
do
    GIT_COMMITTER_DATE=$(git show --format=%ad --no-patch) \
        git commit --amend --gpg-sign --no-edit --allow-empty
    git rebase --continue
done

^{(if you do not have user.signingkey specified, use --gpg-sign=<fingerprint>)}

This will go through each of the edit-marked commit, set the committer's date to match the author's date, keep any empty commit, won't touch the overall patch body and will add a signature with a date of when the command was executed.

Once you see fatal: No rebase in progress? press Ctrl-C to stop the loop and check the logs to confirm that the dates match and the signatures are present everywhere with:

git log --pretty=fuller --show-signature

If everything is okay in the logs, simply issue git push --force and you're done. Now you should see that Verified badge for each commit.

Example with a real history tree. GitHub doesn't seem to care about the signature's date (no reference anywhere), but it'll still be present in the git log.

I have recently needed this and made my own script looking a lot like git-redate

However my scripts does the minimal modifications and takes a lot less time to rewrite (if you need to update) many commits as it does them all at once

change_git_history

Actually this allows to change commit messages too

Explaination:

The scripts concatenates a bunch of bash if-expression looking like so

Here are the ones modifiying the commit date

if [ "$GIT_COMMIT" = "$com_hash" ]; # com is commit
then
    export GIT_AUTHOR_DATE="$com_date";
    export GIT_COMMITTER_DATE="$com_date";
fi;

Here are the ones modifiying the commit message:

if [ true = false ]; # impossible
then
    : # pass
elif [ "$GIT_COMMIT" = "$com_hash" ];
then
    sed 's/.*/$com_msg_esc/g' # replace content with new content
else
    cat - # returns previous content
fi;

And we push all the update using

git filter-branch -f \
    --env-filter "$UPDATES" \
    --msg-filter "$MESSAGES" \
    -- "$REV"

(doc is here filter-branch man)

In addition to Matt Montag's answer:

If you need to reset timestamp to current time after rebase command

git rebase -i HEAD~2

you can use one of these options

pick 4ca564e Do something
exec git commit --amend --no-edit --date=now
pick 1670583 Add another thing
exec git commit --amend --no-edit --reset-author

Both will work