deploy_jdn: show help text if wrong params where given

Signed-off-by: Holger Levsen <holger@layer-acht.org>

deploy_jdn

@@ -15,30 +15,36 @@
 #   use at your own risk. it might eat your cats. you have been warned.
 #   the HOSTS lists below is yet another code duplication…
 
-# useful things:
-# ./deploy_jdn all		- deploy on all nodes (and handle 398 days hosts properly)
-# ./deploy_jdn $host		- deploy on $host and jenkins (and handle 398 days hosts properly)
-# ./deploy_jdn all $foo		- run "$foo" on all nodes (and handle 398 days hosts properly)
-# ./deploy_jdn 			- deploy on jenkins only
-# ./deploy_jdn jenkins		- deploy on jenkins only
-# ./deploy_jdn jenkins ionos10	- deploy on jenkins and ionos10
-# ./deploy_jdn jenkins o167	- deploy on jenkins and osuosl167
-# ./deploy_jdn jenkins c9	- deploy on jenkins and codethink9
-# ./deploy_jdn jenkins 10	- deploy on jenkins and ionos10
-# ./deploy_jdn jenkins 5 6	- deploy on jenkins and ionos5 and ionos6
-# ./deploy_jdn jenkins amd64	- deploy on jenkins and all amd64 nodes
-# ./deploy_jdn only ionos10	- deploy on ionos10
-# ./deploy_jdn only o167	- deploy on osuosl167
-# ./deploy_jdn only c9		- deploy on codethink9
-# ./deploy_jdn only i10		- deploy on ionos10
-# ./deploy_jdn only 5 6		- deploy on ionos5 and ionos6
-# ./deploy_jdn only amd64	- deploy on all amd64 only
-# ./deploy_jdn upgrade|u	- run "apt-get update && upgrade && clean" everywhere
-# ./deploy_jdn upgradey|uy	- run "apt-get upgrade -y" everywhere
-# ./deploy_jdn rmstamp|rm	- delete stamp files everywhere
-#
-# rebooting all of them, except jenkins is easily done like this
-# $ parallel -j 8 -i sh -c 'ssh {} sudo reboot' -- $(./nodes/list_nodes | grep -v jenkins)
+help() {
+cat <<- EOF
+accepted params:
+ ./deploy_jdn all		- deploy on all nodes (and handle 398 days hosts properly)
+ ./deploy_jdn \$host		- deploy on \$host and jenkins (and handle 398 days hosts properly)
+ ./deploy_jdn all \$foo		- run "\$foo" on all nodes (and handle 398 days hosts properly)
+ ./deploy_jdn 			- deploy on jenkins only
+ ./deploy_jdn jenkins		- deploy on jenkins only
+ ./deploy_jdn jenkins ionos10	- deploy on jenkins and ionos10
+ ./deploy_jdn jenkins o167	- deploy on jenkins and osuosl167
+ ./deploy_jdn jenkins c9	- deploy on jenkins and codethink9
+ ./deploy_jdn jenkins 10	- deploy on jenkins and ionos10
+ ./deploy_jdn jenkins 5 6	- deploy on jenkins and ionos5 and ionos6
+ ./deploy_jdn jenkins amd64	- deploy on jenkins and all amd64 nodes
+ ./deploy_jdn only ionos10	- deploy on ionos10
+ ./deploy_jdn only o167		- deploy on osuosl167
+ ./deploy_jdn only c9		- deploy on codethink9
+ ./deploy_jdn only i10		- deploy on ionos10
+ ./deploy_jdn only 5 6		- deploy on ionos5 and ionos6
+ ./deploy_jdn only amd64	- deploy on all amd64 only
+ ./deploy_jdn upgrade|u		- run "apt-get update && upgrade && clean" everywhere
+ ./deploy_jdn upgradey|uy	- run "apt-get upgrade -y" everywhere
+ ./deploy_jdn rmstamp|rm	- delete stamp files everywhere
+
+Rebooting all nodes, except jenkins, is easily done like this:
+ $ parallel -j 8 -i sh -c 'ssh {} sudo reboot' -- \$(./nodes/list_nodes | grep -v jenkins)
+
+EOF
+}
+
 
 START=$(date +'%s')
 GIT_REPO="https://salsa.debian.org/qa/jenkins.debian.net.git"
@@ -151,6 +157,7 @@ elif [ "$1" = "jenkins" ] || [ "$1" = "only" ] ; then
 	echo -n "Running j.d.n.git updates on ${HOSTS[@]} now"
 else
 	echo "I dont understand what to do, please try again."
+	help
 	exit 1
 fi