Hi Paul, Paul Richards wrote: > Is it possible to edit an old commit object and only alter the ID of > the parent commit but otherwise leave all the other information intact > (tree, message, authors, date, etc). > > I'd expect such a command to return the new hash of the modified commit. The standard answer to this question is to say “use grafts and filter-branch”. The git-filter-branch(1) man page explains this approach. It is very powerful, but sometimes I do not want to have that much power. So I will tell a secret: in the scenarios when I wanted something like this (actually, what I have occasionally wanted is to transform a single-parent commit into a merge), I did something like the following: $ git cat-file commit $rev tree dcd2cc4b76f8756423f5c1ab7d2c62d458a8b15f parent 5f1e6d9ce35e212708f9adc55e6b9a7e0d296df4 author Will Palmer <wmpalmer@xxxxxxxxx> 1272275407 -0500 committer Jonathan Nieder <jrnieder@xxxxxxxxx> 1272275443 -0500 pretty: Respect --abbrev option Prior to this, the output of git log -1 --format=%h was always 7 characters long, without regard to whether --abbrev had been passed. Signed-off-by: Will Palmer <wmpalmer@xxxxxxxxx> Signed-off-by: Jonathan Nieder <jrnieder@xxxxxxxxx> $ git cat-file commit $rev >tmp $ sed -i -e "s/parent .*/parent $(git rev-parse othercommit)/" tmp $ git hash-object -t commit -w tmp ca55c560685284ac6d121939b2cd881f426e7074 Easy. Still, I would be happy to see this packaged in a command, so I could recommend it in combination with ‘git replace’ to people who are scared of sed. Thanks for bringing it up. Jonathan -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html