Script to rewrite a list of authors in git history

update-authors.sh

#!/bin/bash


# 
# +-----------------------+
# | Update Authors Script |
# +-----------------------+-------------------------------------------------------------------------+
# |																									|
# | Updates wrong authors and maps them to the new Git authors 							|
# |																									|
# | Dependent on https://github.com/sethwebster/git-rewrite-author/blob/master/git-rewrite-author	|
# | forked from  https://github.com/davidfokkema/git-rewrite-author/blob/master/git-rewrite-author	|
# |																									|
# +-------------------------------------------------------------------------------------------------+
#
#

# Notes (example below in code, please edit)
# 
# 1. Define the correct	authors (examples below: correct_author_*)
# 2. Define the old authors we should remap
# 3. Define the new authors the old author should map to (via position in the array)
# 4. Run via command line
#
# Note: a Git rewrite takes a long time, and you are rewriting history.
# 		
#		Anyone using this repository should:
#
#			git fetch --all
#			git reset --hard origin/master
#


# Download git-rewrite-author
if [ ! -f "git-rewrite-author" ]; then
	curl https://raw2.github.com/sethwebster/git-rewrite-author/master/git-rewrite-author -o git-rewrite-author
	chmod +x git-rewrite-author;
fi

# map out our current correct users
correct_author_1="Seth Webster <[email protected]>"
correct_author_2="Jane Doe <[email protected]>"
correct_author_3="John Moose <[email protected]>"

# old authors
oldauthors[1]="jdoe <jdoe@c0f60b75-22a0-4989-a491-524eb590045c>";
oldauthors[2]="jmoose-admin <jdoe-admin@c0f60b75-22a0-4989-a491-524eb590045c>";
oldauthors[3]="Seth-Admin <sadmin@localhost>";
oldauthors[4]="Jane Doe <[email protected]>";

# map to new authors
newauthors[1]=$correct_author_2;
newauthors[2]=$correct_author_3;
newauthors[3]=$correct_author_1;
newauthors[4]=$correct_author_2;

# indexing function (find old, which maps to new)
find_correct_author ()
{
	for index in ${!oldauthors[*]}
	do
		if [ "$1" == "${oldauthors[$index]}" ] ; then
			echo $index;
			break;
		fi
	done
	return 0;
}


# load the authors who've contributed to this repository
list=$(./git-rewrite-author -l);

# split them into an array
IFS=$'\n' authors=($list)

# iterate over the authors and map them to our new ones
for index in ${!authors[*]}
do
	#we skip our first element because it's the 
	# instructional text from output
	if [[ $index -eq 0 ]] ; then
		continue;
	fi

	# find our old author index (0 = not found)
	item=$(find_correct_author "${authors[$index]}");
	# check if we found old author
	if [[ $item -ne 0 ]] ; then
		# bingo, let's rewrite
		echo "Rewrite ${authors[$index]} to ${newauthors[$item]}"
	
		./git-rewrite-author -w "${oldauthors[$index]}" "${newauthors[$index]}"
		# if our exit code is non-zero, it failed
		if [[ $? -ne 0 ]] ; then
			echo "Rewrite failed."
			break;
		fi
	fi
done

echo
echo "Complete."
echo