git_tricks.md

git filter-branch commands

Case: Migrate sub-directory from one git repo into it's own git repo

$ git filter-branch -f --prune-empty --subdirectory-filter <subdirectory> @

Note: '@' is current branch (or head).

Case: Remove file and history from source tree

$ git filter-branch -f --prune-empty --index-filter 'git rm -rf --cached --ignore-unmatch <dir>' @

Case: Remove all but single directory from source tree

$ git filter-branch -f --prune-empty --index-filter 'git ls-files | egrep -v "^<dir>/*" | \
            xargs git rm -rf --cached --ignore-unmatch' @

Note: Change regex expression to include other folders if necessary (i.e., `"^dir1/|^dir2/|...")

Case: Remove all empty merge commits

$ git filter-branch -f --prune-empty --parent-filter \
            'sed "s/-p //g" | xargs -r git show-branch --independent | sed "s/\</-p /g"'

Note: Pipe error and standard output to /dev/null to clean up output. Append commands with ; true to let filter-branch commands continue if files are not found.

Case: List files in the git history which are not in the working tree

$ git log --raw |awk '/^:/ { if (! printed[$6]) \
            { print $6; printed[$6] = 1 }}'|while read f;do if [ ! -f $f ]; then echo Deleted: $f;fi;done

References

Understanding Git Filter-branch and the Git Storage Model