scripts/deploy: if no host is specified, then deploy to the current host

scripts/deploy

@@ -1,11 +1,12 @@
-#!/bin/sh
+#!/usr/bin/env nix-shell
+#!nix-shell -i bash -p nettools
 
 set -e
 
 usage() {
   echo "deploy: deploy a nix config to a remote machine, possibly activating it"
   echo ""
-  echo "usage: deploy [options] <host>"
+  echo "usage: deploy [options] [host]"
   echo "options:"
   echo "- --action switch|test"
   echo "- --variant light|min"
@@ -13,6 +14,7 @@ usage() {
 }
 
 action=switch
+host=$(hostname)
 variant=
 nixArgs=()
 parseArgs() {