Sync a github fork with all changes from the fork source

sync.sh

#!/bin/sh

# Settings
#
fork_source_remote_name="origin"
my_form_remote_name="mine"
git_default_param=" -q "

#### Stolen from git flow ( https://github.com/nvie/gitflow/ ) ###

escape() {
        echo "$1" | sed 's/\([\.\$\*]\)/\\\1/g'
}
has() {
        local item=$1; shift
        echo " $@ " | grep -q " $(escape $item) "
}

git_local_branches() { git branch --no-color | sed 's/^[* ] //'; }
git_local_branch_exists() { has $1 $(git_local_branches); }
git_remote_origin_branches() { git branch -r --no-color | sed 's/^[* ] //' | grep -v mine | grep -v -- '->'; }

#### Stolen code end ####

origin_branches=`git_remote_origin_branches`

git fetch $git_default_param $fork_source_remote_name

for origin_branch in $origin_branches
do
        stripped_origin_branch=`echo $origin_branch | sed 's/origin\///'`

        if ! git_local_branch_exists $stripped_origin_branch
        then
                git checkout $git_default_param -t $origin_branch
        else
                git checkout $git_default_param $stripped_origin_branch
        fi

        git pull $git_default_param $fork_source_remote_name
        git push $git_default_param $my_form_remote_name
done

git push $git_default_param $my_form_remote_name --prune
git push $git_default_param $my_form_remote_name --mirror