sync_repo.sh

#!/bin/bash
#Synchronize all changes (incl new branches and tags) from repo A to repo B, where B is a bare repo.
#B must be an bare clone of A (initial setup)
#A' must be a clone of A where origin points to A
#There are probably more optimized ways to do this. the advantage of this method is that no branch is deleted from the backup repo
#so the source repo is not 100% trusted

#make sure to define BACKUP_REPO and INTERMEDIARY_REPO

#define where repo B resides (Git repo URL) eg file://${HOME}/path/to/repo.git
BACKUP_REPO="file://${HOME}/path/to/repo.git"
#A' repo location we will cd into
INTERMEDIARY_REPO=${HOME}/repoAPrime

#cd into the A' repo
cd ${INTERMEDIARY_REPO}

get_branches() {
  flags=""
  if [ $2 == "remote" ] ; then
    flags="-r"
  fi
  
  branches=`git branch $flags | sed -e "s/*//g"`
  i=0
  for b in $branches ; do
    cl=`echo $b | sed -e "s:\s*::g" -e "s:origin/::g"`
    eval "$1[$i]=$cl"
    let "i=$i + 1"
  done
}

localize() {
  rb=$1
  if [ $rb == "HEAD" ] ; then
    echo "Not processing HEAD"
  else
    local=$2
    echo "Localizing $rb"
    found="FALSE"
    for l in ${local[*]} ; do
      if [ $found == "FALSE" ] ; then
        if [ $l == $rb ] ; then
          found="TRUE"
        fi
      fi
    done

    if [ $found == "FALSE" ] ; then
      echo "... adding a local branch for $rb"
      git checkout -q -f -b $rb origin/$rb
    else
      echo "... no need to add local branch for $rb"
    fi  
  fi
}

git fetch origin
git fetch --tags origin

get_branches local_branches local
get_branches remote_branches remote

echo "Local: [${local_branches[*]}] and is of size ${#local_branches[*]}"
echo "Remote: [${remote_branches[*]}] and is of size ${#remote_branches[*]}"

for rb in ${remote_branches[*]} ; do
  localize $rb $local_branches
done

unset local_branches
get_branches local_branches local

echo "After localizing, local: [${local_branches[*]}] and is of size ${#local_branches[*]}"

for lb in ${local_branches[*]} ; do
  echo "Updating $lb"
  git checkout -q -f $lb
  git pull -q origin $lb
  git push ${BACKUP_REPO} $lb
done

git push ${BACKUP_REPO} --tags

This script is licensed under Creative Commons so feel free to copy, edit and reuse.