diff --git a/script/package_release.sh b/script/package_release.sh
index 386d00b..fabb55c 100755
--- a/script/package_release.sh
+++ b/script/package_release.sh
@@ -1,19 +1,19 @@
-#!/bin/bash
+#!/usr/bin/env bash
 set -x
 PROJECT=ChatPlaysRTS
 version=$1
 zipfile=$PROJECT-$version.zip
 
-if ! [ -n "$version" ]; then
-	echo "Usage: $(basename $0) version" 1>&2
+if [ -z "$version" ]; then
+	echo "Usage: $(basename "$0") version" 1>&2
 	exit 1
 fi
 
 mkdir -p .tmp/$PROJECT
 files=$(git ls-tree -r HEAD --name-only | grep -v "^\.gitignore$")
-rsync -R $files .tmp/$PROJECT
-pushd .tmp
-zip -r $zipfile $PROJECT
-mv $zipfile ../
-popd
-rm -rf .tmp
+rsync -R "$files" .tmp/$PROJECT
+pushd .tmp || exit 1
+zip -r "$zipfile" $PROJECT
+mv "$zipfile" ../
+popd || exit 1
+rm -rf .tmp