shell script for upgrading postgres 9.3 to 9.4 with postGIS. RUN AS ROOT

upgrade_postgresql_9.3_to_9.4.sh

#! /bin/bash
#
# Based on http://www.gab.lc/articles/migration_postgresql_9-3_to_9-4
#

# Make sure only root can run our script
if [ "$(id -u)" != "0" ]; then
   echo "This script must be run as root" 1>&2
   exit 1
fi

cd /tmp
sudo -u postgres pg_dumpall > BkpOldPG.sql

# make an extra backup so a system restart somewhere in here doesn't wipe it out.
cp /tmp/BkpOldPG.sql /home/BkpOldPG.sql

# If no backup
if [[ ! $(find /tmp/BkpOldPG.sql -type f -size +1c 2>/dev/null) ]]; then
  echo "Something went wrong and a backup could not be created! Exiting..."
  exit 1

fi

apt-get update
# apt-get upgrade
apt-get install postgresql-9.4 postgresql-9.4-postgis-2.1

/etc/init.d/postgresql stop

# backup default config files before replacing them
cd /etc/postgresql/9.4/main/
cp pg_hba.conf pg_hba.conf_default # backup pg_hba.conf
cp postgresql postgresql.conf_default # backup postgresql.conf

# Replace new config files with old ones
cp ../../9.3/main/pg_hba.conf ./ # copy pg_hba.conf from old version
cp ../../9.3/main/postgresql.conf ./ # copy postgresql.conf from old version

# Replaces references to the old version (9.3) in the replaced config files
sed -i 's/9.3/9.4/g' postgresql.conf

# Check the replacement
grep '9.' postgresql.conf
# Output should look like:
# data_directory = '/var/lib/postgresql/9.4/main'        # use data in another directory
# hba_file = '/etc/postgresql/9.4/main/pg_hba.conf'    # host-based authentication file
# ident_file = '/etc/postgresql/9.4/main/pg_ident.conf'    # ident configuration file
# external_pid_file = '/var/run/postgresql/9.4-main.pid'            # write an extra PID file

# change the configuration of the old version to keep it from starting
#  replaces the last line "auto" by "disabled"
sed -i '7,/auto/{s/auto/disabled/}' /etc/postgresql/9.3/main/start.conf

##########################################
echo
read -n1 -rsp $'Press any key to start postgres 9.4 or Ctrl+C to exit...\n'

# Try to start postgreSQL 9.4
/etc/init.d/postgresql start
# [ ok ] Starting PostgreSQL 9.3 database server:.
# [ ok ] Starting PostgreSQL 9.4 database server: main.

# Restore the backups from the old version
cd /tmp
sudo -u postgres /usr/lib/postgresql/9.4/bin/psql -d postgres -f BkpOldPG.sql

# In case  you rebooted the server and lost the content of /tmp, you can use the copy of the backup that we made in /home/BkpOldPG.sql

# Check the new version
sudo -u postgres psql -c "SHOW SERVER_VERSION"

##########################################
echo
read -n1 -rsp $'Press any key if above version looks correct or Ctrl+C to exit...\n'

# Remove the old version
#    `dpkg -l | grep postgresql`
# We now just have to remove all the packages relative to 9.3
# The list might depend with your installation.
apt-get remove postgresql-9.3 postgresql-9.3-ip4r postgresql-9.3-postgis-2.1 postgresql-9.3-postgis-scripts postgresql-client-9.3 postgresql-contrib-9.3