Upgrades postgres 9.1 to 9.3 with PostGIS 2.1 on Ubuntu (precise)

up_postgres.sh

echo "deb http://apt.postgresql.org/pub/repos/apt/ precise-pgdg main" | sudo tee -a /etc/apt/sources.list.d/pgdg.list
 
wget --quiet -O - http://apt.postgresql.org/pub/repos/apt/ACCC4CF8.asc | sudo apt-key add -
sudo apt-get update
sudo apt-get upgrade
 
 
sudo apt-get install postgresql-9.3 postgresql-9.3-postgis-2.1 postgresql-contrib-9.3 libpq-dev postgresql-9.3-postgis-2.1
 
cd /tmp
 
sudo service postgresql stop
 
sudo -H -u postgres /usr/lib/postgresql/9.3/bin/pg_upgrade \
   -b /usr/lib/postgresql/9.1/bin \
   -B /usr/lib/postgresql/9.3/bin \
   -d /var/lib/postgresql/9.1/main \
   -D /var/lib/postgresql/9.3/main \
   -o ' -c config_file=/etc/postgresql/9.1/main/postgresql.conf' \
   -O ' -c config_file=/etc/postgresql/9.3/main/postgresql.conf'
 
sudo service postgresql start

To disable a pg cluster - change auto to disabled in /etc/postgresql/9.1/main/start.conf

Look at using pg_upgrade with --jobs and --links to speed up upgrade