How do I remove the old history from a git repository

Question

I m afraid I couldn t find anything quite like this particular scenario   I have a git repository with a lot of history  500  branches  500  tags  going back to mid-2007  It contains  19 500 commits  We d like to remove all of the history before Jan 1  2010  to make it smaller and easier to deal with  we would keep a complete copy of the history in an archive repository    I know the commit that I want to have become the root of the new repository  I can t  however  figure out the correct git mojo to truncate the repo to start with that commit  I m guessing some variant of   git filter-branch   involving grafts would be necessary  it might also be necessary to treat each of the 200  branches we want to keep separately and then patch the repo back together  something I do know how to do    Has anyone ever done something like this  I ve got git 1 7 2 3 if that matters

User · Accepted Answer

Just create a graft of the parent of your new root commit to no parent (or to an empty commit, e.g. the real root commit of your repository). E.g. echo "<NEW-ROOT-SHA1>" > .git/info/grafts

After creating the graft, it takes effect right away; you should be able to look at git log and see that the unwanted old commits have gone away:

$ echo 4a46bc886318679d8b15e05aea40b83ff6c3bd47 > .git/info/grafts
$ git log --decorate | tail --lines=11
commit cb3da2d4d8c3378919844b29e815bfd5fdc0210c
Author: Your Name <[email protected]>
Date:   Fri May 24 14:04:10 2013 +0200

    Another message

commit 4a46bc886318679d8b15e05aea40b83ff6c3bd47 (grafted)
Author: Your Name <[email protected]>
Date:   Thu May 23 22:27:48 2013 +0200

    Some message

If all looks as intended, you can just do a simple git filter-branch -- --all to make it permanent.

BEWARE: after doing the filter-branch step, all commit ids will have changed, so anybody using the old repo must never merge with anyone using the new repo.

User · Answer

Maybe it s too late to post a reply  but as this page is the first Google s result  it may still be helpful   If you want to free some space in your git repo  but do not want to rebuild all your commits  rebase or graft   and still be able to push pull merge from people who has the full repo  you may use the git clone shallow clone  --depth parameter      Clone the original repo into limitedRepo git clone file    path to originalRepo limitedRepo --depth 10    Remove the original repo  to free up some space rm -rf originalRepo cd limitedRepo git remote rm origin   You may be able to shallow your existing repo  by following these steps     Shallow to last 5 commits git rev-parse HEAD 5  gt   git shallow    Manually remove all other branches  tags and remotes that refers to old commits    Prune unreachable objects git fsck --unreachable   Will show you the list of what will be deleted git gc --prune now       Will actually delete your data   How to remove all git local tags   Ps  Older versions of git didn t support clone push pull from to shallow repos

User · Answer

remove git data  rm  git git init add a git remote force push

User · Answer

When rebase or push to head master this error may occurred   remote  GitLab  You are not allowed to access some of the refs  To git giturl main xyz git     remote rejected  master - gt  master  pre-receive hook declined  error  failed to push some refs to  git giturl main xyz git    To resolve this issue in git dashboard should remove master branch from  Protected branches     then you can run this command   git push -f origin master   or  git rebase --onto temp  1 master

User · Answer

As an alternative to rewriting history  consider using git replace as in this article from the Pro Git book  The example discussed involves replacing a parent commit to simulate the beginning of a tree  while still keeping the full history as a separate branch for safekeeping

User · Answer

I needed to read several answers and some other info to understand what I was doing   1  Ignore everything older than a certain commit  The file  git info grafts can define fake parents for a commit  A line with just a commit id  says that the commit doesn t have a parent  If we wanted to say that we care only about the last 2000 commits  we can type   git rev-parse HEAD 2000  gt   git info grafts   git rev-parse gives us the commit id of the 2000th parent of the current commit  The above command will overwrite the grafts file if present  Check if it s there first   2  Rewrite the Git history  optional   If you want to make this grafted fake parent a real one  then run   git filter-branch -- --all   It will change all commit ids  Every copy of this repository needs to be updated forcefully   3  Clean up disk space  I didn t done step 2  because I wanted my copy to stay compatible with the upstream  I just wanted to save some disk space  In order to forget all the old commits   git prune git gc   Alternative  shallow copies  If you have a shallow copy of another repository and just want to save some disk space  you can update  git shallow  But be careful that nothing is pointing at a commit from before  So you could run something like this   git fetch --prune git rev-parse HEAD 2000  gt   git shallow git prune git gc   The entry in shallow works like a graft  But be careful not to use grafts and shallow at the same time  At least  don t have the same entries in there  it will fail   If you still have some old references  tags  branches  remote heads  that point to older commits  they won t be cleaned up and you won t save more disk space

User · Answer

If you want to keep the upstream repository with full history  but local smaller checkouts  do a shallow clone with git clone --depth 1  repo    After pushing a commit  you can do    git fetch --depth 1 to prune the old commits  This makes the old commits and their objects unreachable  git reflog expire --expire-unreachable now --all  To expire all old commits and their objects git gc --aggressive --prune all to remove the old objects   See also How to remove local git history after a commit    Note that you cannot push this  shallow  repository to somewhere else   shallow update not allowed   See Remote rejected  shallow update not allowed  after changing Git remote URL  If you want to to that  you have to stick with grafting

User · Answer

According to the Git repo of the BFG tool  it  quot removes large or troublesome blobs as git-filter-branch does  but faster - and is written in Scala quot   https   github com rtyley bfg-repo-cleaner

User · Answer

There are too many answers here which are not current and some don t fully explain the consequences  Here s what worked for me for trimming down the history using latest git 2 26   First create a dummy commit  This commit will appear as the first commit in your truncated repo  You need this because this commit will hold all base files for the history you are keeping  The SHA is the ID of the previous commit of the commit you want to keep  in this example  8365366   The string  Initial  will show up as commit message of the first commit  If you are using Windows  type below command from Git Bash command prompt     8365366 is id of parent commit after which you want to preserve history echo  Initial    git commit-tree 8365366  tree    Above command will print SHA  for example  d10f7503bc1ec9d367da15b540887730db862023   Now just type     d10f750 is commit ID from previous command git rebase --onto d10f750 8365366   This will first put all files as-of commit 8365366 in to the dummy commit d10f750  Then it will play back all commits after 8365366 over the top of d10f750  Finally master branch pointer will be updated to last commit played back   Now if you want to push these truncated repo  just do git push -f   Few things to keep in mind  these applies to other methods as well as this one   Tags are not transferred  While commit IDs and timestamps are preserved  you will see GitHub show these commits in lumpsum heading like Commits on XY date   Fortunately it is possible to keep truncated history as  archive  and later you can join back trimmed repo with archive repo  For doing this  see this guide

User · Answer

Try this method How to truncate git history       bin bash git checkout --orphan temp  1 git commit -m  Truncated history  git rebase --onto temp  1 master git branch -D temp   Here  1 is SHA-1 of the commit you want to keep and the script will create new branch that contains all commits between  1 and master and all the older history is dropped  Note that this simple script assumes that you do not have existing branch called temp  Also note that this script does not clear the git data for old history  Run git gc --prune all  amp  amp  git repack -a -f -F -d after you ve verified that you truly want to lose all history  You may also need rebase --preserve-merges but be warned that the git implementation of that feature is not perfect  Inspect the results manually if you use that

User · Answer

This method is easy to understand and works fine  The argument to the script   1  is a reference  tag  hash       to the commit starting from which you want to keep your history      bin bash git checkout --orphan temp  1   create a new branch without parent history git commit -m  Truncated history    create a first commit on this branch git rebase --onto temp  1 master   now rebase the part of master branch that we want to keep onto this branch git branch -D temp   delete the temp branch    The following 2 commands are optional - they keep your git repo in good shape  git prune --progress   delete all the objects w o references git gc --aggressive   aggressively collect garbage  may take a lot of time on large repos   NOTE that old tags will still remain present  so you might need to remove them manually  remark  I know this is almost the same aswer as  yoyodin  but there are some important extra commands and informations here  I tried to edit the answer  but since it is a substantial change to  yoyodin s answer  my edit was rejected  so here s the information

[git] How do I remove the old history from a git repository?

Examples related to git

Examples related to git-filter-branch