+function printUsage()
+{
+ cat <<EOT
+Usage: "$PN_" [OPTIONS] <tun0> <tun1> ...
+
+$PN_ creates persistent tun/tap devices with bridge handling
+
+OPTIONS:
+ -d delete the tun devices and remove them from the bridge if given
+ -u <user> this user should be able to use the tun device
+ -g <group> this group should be able to use the tun device
+ -b <bridge> if given, all tun/tap devices are added/removed from the bridge
+ -a enable auto mode, eg. create the bridge if not already existing and
+ delete it when empty after removing given tun devices
+ -h this help
+EOT
+}