GitLab postuninstall scriptlet (using /bin/sh):

gitlab-postun.sh

#!/bin/sh
# WARNING: REQUIRES /bin/sh
#
# - must run on /bin/sh on solaris 9
# - must run on /bin/sh on AIX 6.x
# - if you think you are a bash wizard, you probably do not understand
#   this programming language.  do not touch.
# - if you are under 40, get peer review from your elders.

is_smartos() {
  uname -v | grep "^joyent" 2>&1 >/dev/null
}

if is_smartos; then
    PREFIX="/opt/local"
else
    PREFIX="/usr"
fi

cleanup_symlinks() {
  binaries="gitlab-ctl gitlab-rake gitlab-rails gitlab-psql"
  for binary in $binaries; do
    rm -f $PREFIX/bin/$binary
  done
}

# Clean up binary symlinks if they exist
# see: http://tickets.opscode.com/browse/CHEF-3022
if [ ! -f /etc/redhat-release -a ! -f /etc/fedora-release -a ! -f /etc/system-release ]; then
  # not a redhat-ish RPM-based system
  cleanup_symlinks
elif [ "x$1" = "x0" ]; then
  # RPM-based system and we're deinstalling rather than upgrading
  cleanup_symlinks
fi
posttrans scriptlet (using /bin/sh):
#!/bin/sh
# GitLab post-transition script
# RPM only
DEST_DIR=/opt/gitlab


if [ -e /etc/gitlab/gitlab.rb ] ; then
  EXTERNAL_URL=$(awk '/^external_url/ { print $2 }' /etc/gitlab/gitlab.rb | tr -d "'\"")
fi

check_if_ec2()
{
  if [ -f /sys/hypervisor/uuid ] && [ `head -c 3 /sys/hypervisor/uuid` = 'ec2' ]; then
    return 0
  else
    return 1
  fi
}

get_ec2_address()
{
  url=$1
  # Try collecting fqdn if it is set correctly
  fqdn=$(/opt/gitlab/embedded/bin/curl -s ${url})
  if [ -n "${fqdn}" ]; then
    # Checking if curl returned an XML message
    word="<?xml"
    if ! $(test "${fqdn#*$word}" != "$fqdn"); then
        EXTERNAL_URL="http://${fqdn}"
    fi
  fi
}

get_details_from_ec2()
{
  get_ec2_address "http://169.254.169.254/latest/meta-data/public-hostname"
  if [ -z "${EXTERNAL_URL}" ]; then
    get_ec2_address "http://169.254.169.254/latest/meta-data/public-ipv4"
  fi
}

set_protocol()
{
  # Checking if EXTERNAL_URL starts with http:// or https://
  if ! $(echo ${EXTERNAL_URL} | awk '$0 !~ /^http[s]?:\/\// {exit 1}'); then
    EXTERNAL_URL="http://${EXTERNAL_URL}"
  fi
}

if [ -z "${EXTERNAL_URL}" ]; then
  check_if_ec2
  if [ $? -eq 0 ]  ; then
    get_details_from_ec2
  fi
else
    set_protocol
fi

if [ -z "${EXTERNAL_URL}" ]; then
  EXTERNAL_URL="http://gitlab.example.com"
fi


case "$1" in
  0)
    # RPM install/upgrade
    ${DEST_DIR}/embedded/bin/symlink_ctl_cmds ${DEST_DIR}
    EXTERNAL_URL=${EXTERNAL_URL} ${DEST_DIR}/bin/gitlab-ctl upgrade
    ;;
  *)
    # Noop.
    ;;
esace