* Changed pivpn command exit codes from 1 to 0

- exit code 1 means general error hence should not be used for exiting successfully
* added backup script to backup openvpn and pivpn generated certificates
* added update script to update /opt/pivpn scripts, -t | --test | test update from test branch
* Fixed hostname length issue #831
    - the script now checks for hostname length right at the beginning and prompts for a new one.
    - HOST_NAME to host_name, as best practice variables with capitals, should be used by system variables only.
* fixed ubuntu 18.04 being detected as not supported OS, now fully supported and tested.
* changed how scripts are copied to /opt/pivpn, it hat a lot of long repetitive lines, now it copies all *.sh files making it easier to manage when adding new scripts/features
* Changed how supported OS are presented when maybeOS_Support() is called.

scripts/backup.sh

@@ -0,0 +1,31 @@
+#!/bin/bash
+install_user=$(</etc/pivpn/INSTALL_USER)
+install_home=$(grep -m1 "^${install_user}:" /etc/passwd | cut -d: -f6)
+install_home=${install_home%/} # remove possible trailing slash
+backupdir=pivpnbackup
+openvpndir=/etc/openvpn
+ovpnsdir=${install_home}/ovpns
+date=$(date +%Y-%m-%d-%H%M%S)
+
+backup_openvpn(){
+  if [[ ! -d $install_home/$backupdir ]]; then
+     mkdir $install_home/$backupdir
+  fi
+  cp -r $openvpndir $ovpnsdir $backupdir 2&>1
+  backupzip=$date-pivpnbackup.tgz
+  tar -czf $backupzip -C ${install_home} $backupdir 2&>1
+  echo -e "Backup crated to $install_home/$backupdir/$backupzip \nTo restore the backup, follow instructions at:\nhttps://github.com/pivpn/pivpn/wiki/FAQ#how-can-i-migrate-my-configs-to-another-pivpn-instance" 
+}
+
+
+if [[ ! $EUID -eq 0 ]];then
+  if [[ $(dpkg-query -s sudo) ]];then
+        export SUDO="sudo"
+  else
+    echo "::: Please install sudo or run this as root."
+    exit 0
+  fi
+fi
+
+backup_openvpn
+

scripts/update.sh

@@ -0,0 +1,99 @@
+#/bin/bash
+
+###Updates pivpn scripts (Not PiVPN)
+###Main Vars
+pivpnrepo="https://github.com/pivpn/pivpn.git"
+pivpnlocalpath="/etc/.pivpn"
+pivpnscripts="/opt/pivpn/scripts"
+bashcompletiondir="/etc/bash_completion.d/pivpn"
+
+
+###Functions
+##Updates scripts
+updatepivpnscripts(){
+    ##We don't know what sort of changes users have made. 
+    ##Lets remove first /etc/.pivpn dir then clone it back again
+    echo "going do update PiVPN Scripts"
+    if [[ -d $pivpnlocalpath ]]; then
+
+        sudo rm -rf $pivpnlocalpath
+        cloneandupdate
+
+    else
+        cloneandupdate
+    fi
+    echo "PiVPN Scripts have been updated"
+}
+
+##Updates scripts using test branch 
+updatefromtest(){
+    ##We don't know what sort of changes users have made. 
+    ##Lets remove first /etc/.pivpn dir then clone it back again
+    echo "PiVPN Scripts updating from test branch"
+    if [[ -d /etc/.pivpn ]]; then
+
+        rm -rf /etc/.pivpn
+        cloneupdttest
+
+    else
+
+        cloneupdttest
+
+    fi
+    echo "PiVPN Scripts updated have been updated from test branch"
+  }
+
+##Clone and copy pivpn scripts to /op/
+cloneandupdate(){
+
+        sudo git clone $pivpnrepo $pivpnlocalpath
+        sudo cp -r $pivpnlocalpath/scripts $pivpnscripts
+        sudo cp $pivpnlocalpath/scripts/bash-completion $bashcompletiondir
+
+}
+
+##same as cloneandupdate() but from test branch
+##and falls back to master branch again after updating
+cloneupdttest(){
+
+        sudo git clone $pivpnrepo $pivpnlocalpath
+        sudo git -C $pivpnlocalpath checkout test
+        sudo git -C $pivpnlocalpath pull origin test
+        sudo cp -r $pivpnlocalpath/scripts $pivpnscripts
+        sudo cp $pivpnlocalpath/scripts/bash-completion $bashcompletiondir
+        sudo git -C $pivpnlocalpath checkout master
+
+}
+
+scriptusage(){
+    echo -e "Updates pivpn scripts,\n
+              Usage:
+              pivpn update              | updates from master branch
+              pivpn update -t or --test | updates from test branch"
+
+}
+
+## SCRIPT
+
+if [[ $# -eq 0 ]]; then
+    updatepivpnscripts
+
+else
+  while true; do
+    case "$1" in
+      -t | --test | test )
+          updatefromtest
+          exit 0
+          ;;
+      -h | --help | help )
+          scriptusage
+          exit 0
+          ;;
+      * ) 
+        updatepivpnscripts 
+        exit 0
+        ;;
+    esac
+  done
+fi
+