move the user-interactive questions and other parts of start.sh into new files

setup/preflight.sh

@@ -0,0 +1,29 @@
+# Are we running as root?
+if [[ $EUID -ne 0 ]]; then
+	echo "This script must be run as root. Please re-run like this:"
+	echo
+	echo "sudo setup/start.sh"
+	echo
+	exit
+fi
+
+# Check that we are running on Ubuntu 14.04 LTS (or 14.04.xx).
+if [ "`lsb_release -d | sed 's/.*:\s*//' | sed 's/14\.04\.[0-9]/14.04/' `" != "Ubuntu 14.04 LTS" ]; then
+	echo "Mail-in-a-Box only supports being installed on Ubuntu 14.04, sorry. You are running:"
+	echo
+	lsb_release -d | sed 's/.*:\s*//'
+	echo
+	echo "We can't write scripts that run on every possible setup, sorry."
+	exit
+fi
+
+# Check that we have enough memory. Skip the check if we appear to be
+# running inside of Vagrant, because that's really just for testing.
+TOTAL_PHYSICAL_MEM=$(free -m | grep ^Mem: | sed "s/^Mem: *\([0-9]*\).*/\1/")
+if [ $TOTAL_PHYSICAL_MEM -lt 768 ]; then
+if [ ! -d /vagrant ]; then
+	echo "Your Mail-in-a-Box needs more than $TOTAL_PHYSICAL_MEM MB RAM."
+	echo "Please provision a machine with at least 768 MB, 1 GB recommended."
+	exit
+fi
+fi