Adds completion for rsh

kubectl_complete-rsh

@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+
+# If we are completing a flag, use Cobra's builtin completion system.
+# To know if we are completing a flag we need the last argument starts with a `-` and does not contain an `=`
+args=("$@")
+lastArg=${args[((${#args[@]}-1))]}
+if [[ "$lastArg" == -* ]]; then
+   if [[ "$lastArg" != *=* ]]; then
+      kubectl ns __complete "$@"
+   fi
+else
+   # TODO Make sure we are not completing the value of a flag.
+   # TODO Only complete a single argument.
+   # Both are pretty hard to do in a shell script.  The better way to do this would be to let
+   # Cobra do all the completions by using `cobra.ValidArgsFunction` in the program.
+   # But the below, although imperfect, is a nice example for plugins that don't use Cobra.
+
+   kubectl get nodes --no-headers -o custom-columns=":metadata.name"
+
+   # Turn off file completion.  See the ShellCompDirective documentation within
+   # https://github.com/spf13/cobra/blob/main/shell_completions.md#completion-of-nouns
+   echo :4
+fi