Question

I wish to update the usernames for a user in the Git history, is this possible?

It was a blunder of mine, I migrated from CVS a while ago and didn’t realise until everyone started using the Git repo that I missed a few usernames.

Answer 1

You want git-filter-branch. As an example, to change the email address of every commit in the entire history, you can do:

$ git filter-branch --env-filter GIT_AUTHOR_EMAIL=new_address

You can set up the filter to only modify commits based on whatever criteria you need. For example, if you want to set the email address for all the commits authored by “Barry”, do

$ git filter-branch --env-filter '
if test "$GIT_AUTHOR_NAME" = Barry; then
  GIT_AUTHOR_EMAIL=barrys-correct-address
fi'

This will modify the SHA1s of every commit.