git_fetch_last_release.sh

#!/bin/bash

_help_for_r() {
  printf -- '\t-r\n\n'
  printf '\tDefines the GIT repository, MANDATORY.\n\n'
  printf '\tUsage\n'
  printf '\t=====\n\n'
  printf "\t-r 'https://github.com/PintaProject/Pinta.git\n"
}

_help_for_t() {
  printf -- '\t-t\n\n'
  printf '\tDefines the tag, by default the last one.\n\n'
  printf '\tUsage\n'
  printf '\t=====\n\n'
  printf "\t-t '1.7'\n"
}

_help_for_d() {
  printf -- '\t-d\n\n'
  printf '\tDefines the git directory, by default git.\n\n'
  printf '\tUsage\n'
  printf '\t=====\n\n'
  printf "\t-d 'my_git_directory'\n"
}

_help() {
  _help_for_r
  printf '\n'
  _help_for_t
  printf '\n'
  _help_for_d
  printf '\n'
}

_checkout(){
  cd ${FETCHING_DIRECTORY}
  git checkout ${TAG};
  if [[ ! ${?} == 0 ]]; then
    echo "The checkout of the tag failed." 1>&2;
    exit 1;
  fi
}

cd
GIT="git"
while getopts :r:t:d:h opt; do
  case ${opt} in
    r)
      GIT_REPOSITORY=$OPTARG;;
    t)
      TAG=$OPTARG;;
    d)
      GIT=$OPTARG;;
    h)
      _help;;
    *)
      _help;;
  esac
done
if [[ ! -z ${GIT_REPOSITORY} ]]; then
  GIT_DIRECTORY=$(echo "${GIT_REPOSITORY##*/}")
  GIT_DIRECTORY=$(echo "${GIT_DIRECTORY%.git}") 
  if [[ -z $TAG ]]; then
    TAGS=`git ls-remote -t --refs $GIT_REPOSITORY`
    TAG=`echo "${TAGS##*/}"`
  fi
  FETCHING_DIRECTORY="${HOME}/${GIT}/${GIT_DIRECTORY}"
  printf 'Git remote repository : %s\n' ${GIT_REPOSITORY}
  printf 'The slected tag is    : %s\n' ${TAG}
  printf 'Git directory         : %s\n' ${GIT}
  printf 'Fetching directory    : %s\n' ${FETCHING_DIRECTORY}
  if [[ ! -d ${GIT} ]]; then
    printf "Creation of the %s directory.\n"
    mkdir ${HOME}/${GIT}
    if [[ ! ${?} = 0 ]]; then
      echo "The creation of the %GIT directory is not possible" 1>&2
      exit 1
    fi
  fi
  cd ${HOME}/${GIT}
  if [[ ! -d ${FETCHING_DIRECTORY} ]]; then 
    git clone ${GIT_REPOSITORY}
    if [[ ! ${?} = 0 ]]; then
      echo "The cloning of ${GIT_REPOSITORY} failed." 1>&2; 
      exit 1;
    fi
  fi 
  _checkout
else
  echo "The git repository is unknown." 1>&2
  exit 1
fi