Abort on linux platform if rclone/age is not found

comp-backup-install.sh

@@ -102,8 +102,17 @@ elif [ $HOST_OS = 'Linux' ]; then
     NOTIFY0='notify-send -a "DTU Compute backup script" -i network-transmit "Backup done"'
     NOTIFY1='notify-send -a "DTU Compute backup script" -i network-error "Backup did not complete"'
     # Check for necessary programs - XXX resolve / provide solution
-    which rclone &>/dev/null || echo -e "\nrclone command not installed\n"
-    which age &>/dev/null || echo -e "\nage command not installed\n"
+    which rclone &>/dev/null
+    if [ $? -ne 0 ] ; then
+	echo -e "\nrclone command not installed\n"
+	exit 1
+    fi
+    
+    which age &>/dev/null
+    if [ $? -ne 0 ] ; then
+	echo -e "\nrage command not installed\n"
+	exit 1
+    fi
     # SYSTEMD
     which systemctl &>/dev/null
     if [ $? -ne 0 ]; then