Release script using git and maven release plugin. Based on the "successful git branch model" and https://gist.github.com/searls/1043970 Its also managed the hotfix feature

release-git-script

#!/bin/bash 

# How to perform a release with git & maven following the git flow conventions
# ----------------------------------------------------------------------------
# Finding the next version: you can see the next version by looking at the
#	version element in "pom.xml" and lopping off "-SNAPSHOT". To illustrate,
#	if the pom's version read "0.0.2-SNAPSHOT", the following instructions would
#	perform the release for version "0.0.2" and increment the development version
#	of each project to "0.0.3-SNAPSHOT".
#
#  If you need to specify the local branch to release (it needs to be created)
#  release.sh --branch <name_local_branch>
#  release.sh -b <name_local_branch>
#
#  Specify is a hotfix branch / it will merge on 'MASTER' and 'DEVELOP'
#  release.sh -hf <true/false>
#  release.sh --hotfix <true/false>
#
#  Specify maven arguments (during release/perform goal)
#  release.sh --maven_args <arguments>
#
#
#  [REQUIRED] need the libxml-xpath-perl / sudo apt-get install  libxml-xpath-perl
#
# Read the version
version=`xpath -q -e "/project/version/text()" pom.xml`
description=`xpath -q -e "/project/description/text()" pom.xml`
version_release=${version%-SNAPSHOT}

### Parameters
hotfix=false
default_branch=develop
maven_args=''


while [ $# -gt 1 ] ; do
case $1 in
-b) default_branch=$2 ; shift 2 ;;
--branch) default_branch=$2 ; shift 2 ;;
-hf) hotfix=$2 ; shift 2 ;;
--hotfix) hotfix=$2 ; shift 2 ;;
--maven_args) maven_args=$2 ; shift 2 ;;
*) shift 1 ;;
esac
done

function assert_snapshot_version(){
    if [[ "$version" != *-SNAPSHOT* ]]; then
      echo "fatal - Cannot release the project is not a SNAPSHOT version."
      echo "[###] Released v$version_release [FAILED]"
      exit 1
    fi
}

function assert_branch_version_exist(){
    git show-ref --verify --quiet "refs/heads/release/v$version_release"
    if [ $? -eq 0 ]; then
      echo "fatal - A local branch already exist release/v$version_release."
      echo "[###] Released v$version_release [FAILED]"
      exit 1
    fi


    git ls-remote --exit-code . "origin/release/v$version_release" &> /dev/null
    if [ $? -eq 0 ]; then
      echo "fatal - A remote branch already exist release/v$version_release."
      echo "[###] Released v$version_release [FAILED]"
      exit 1
    fi
}

function assert_tag_version_exist(){
    git show-ref --verify --quiet "refs/tags/v$version_release"
    if [ $? -eq 0 ]; then
      echo "fatal - A local tag already exist tags/v$version_release."
      echo "[###] Released v$version_release [FAILED]"
      exit 1
    fi

    git ls-remote --exit-code . "tags/v$version_release" &> /dev/null
    if [ $? -eq 0 ]; then
      echo "fatal - A remote tag already exist tags/v$version_release."
      echo "[###] Released v$version_release [FAILED]"
      exit 1
    fi
}

function maven_release(){
    echo "[#] Perform maven release"
    # perform a maven release, which will tag this branch and deploy artifacts to artifactory (http://apps.axon-id.com/artifactory/)
    mvn release:prepare $maven_args 
    if [ $? -ne 0 ]; then
      echo 'fatal: Cannot do mvn release:prepare'
      echo "[###] Released v$version_release [FAILED]"
      exit 1
    fi

    mvn release:perform $maven_args
    if [ $? -ne 0 ]; then
      echo "fatal - Cannot do mvn release:perform"
      echo "[###] Released v$version_release [FAILED]"
      exit 1
    fi

    mvn release:clean $maven_args
    if [ $? -ne 0 ]; then
      echo "fatal - Cannot do mvn release:clean"
      echo "[###] Released v$version_release [FAILED]"
      exit 1
    fi
}

function maj_master_branch(){
    echo "[#] MAJ branch master"
    git checkout master
    git pull origin master

     if [ $? -ne 0 ]; then
      echo "fatal - Cannot pull branch 'master'"
      echo "[###] Released v$version_release [FAILED]"
      exit 1
    fi
}

function maj_default_branch(){
    echo "[#] MAJ branch $default_branch"
    git checkout $default_branch
    git pull origin $default_branch

     if [ $? -ne 0 ]; then
      echo "fatal - Cannot pull branch $default_branch"
      echo "[###] Released v$version_release [FAILED]"
      exit 1
    fi
}


echo "-----------------------------------------------------------------------"
echo " Release $description $version to $version_release "
echo " (local branch : $default_branch) "
echo "-----------------------------------------------------------------------"

assert_snapshot_version
assert_branch_version_exist
assert_tag_version_exist

maj_master_branch
maj_default_branch

echo "[#] create branch release/v$version "
## branch from develop to a new release branch
git checkout $default_branch
git checkout -b release/v$version_release

maven_release

echo "[#] Merge release/v$version_release to develop"
## merge the version changes back into develop so that folks are working against the new release ("0.0.3-SNAPSHOT", in this case)
git checkout $default_branch
git merge --no-ff release/v$version_release

## housekeeping -- rewind the release branch by one commit to fix its version at "0.0.2"
##	excuse the force push, it's because maven will have already pushed '0.0.3-SNAPSHOT'
##	to origin with this branch, and I don't want that version (or a diverging revert commit)
##	in the release or master branches.
git checkout release/v$version_release
git reset --hard HEAD~1
git push --force origin release/v$version_release
git checkout $default_branch

echo "[#] Merge release/v$version_release to Master"

## finally, if & when the code gets deployed to production
git checkout master
git merge --no-ff release/v$version_release
git push --all && git push --tags

if $hotfix ; then
    echo "[!] hotfix activated, going to merge on branch 'develop'"
    git checkout develop
    git pull origin develop
    git merge --no-ff release/v$version_release
    git push origin HEAD
fi

##delete branch release local and remote
git branch -d release/v$version_release
git push origin :release/v$version_release

echo "[###] Released v$version_release [SUCCESS]"