csshX: add page (#3438)

pages/osx/csshX.md

@@ -0,0 +1,16 @@
+# csshX
+
+> Cluster SSH tool for MacOS.
+> More information: <https://github.com/brockgr/csshx>.
+
+- Connect to multiple hosts:
+
+`csshX {{hostname1}} {{hostname2}}`
+
+- Connect to multiple hosts with a given SSH key:
+
+`csshX {{user@hostname1}} {{user@hostname2}} '--ssh_args' '-i {{path/to/ssh_key.pem}}'`
+
+- Connect to a pre-defined cluster from /etc/clusters:
+
+`csshX cluster1`