add batch command script

for

@@ -0,0 +1,26 @@
+#!/bin/bash
+
+set -o errexit -o nounset -o pipefail
+
+[[ $# -eq 2 ]] || exit 1
+
+input=
+read -p "Run command '$2' across $1 servers? " input
+if [[ $input != yes ]]; then
+    exit 1
+fi
+echo
+
+user=root
+
+. hosts.sh
+
+declare -n hosts=hosts_$1
+for host in ${hosts[@]}; do
+    echo $host
+    echo
+
+    ssh $user@$host "$2"
+
+    echo
+done