From 2f3ee624c548de95c0c3a2eb5aa1e154d2f09856 Mon Sep 17 00:00:00 2001
From: Simon Ruderich <simon@ruderich.org>
Date: Sat, 5 Dec 2015 14:25:11 +0100
Subject: [PATCH] use [ -z .. ] instead of explicit compare with ""

---
 letsencrypt.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/letsencrypt.sh b/letsencrypt.sh
index eb72b3d..361ab30 100755
--- a/letsencrypt.sh
+++ b/letsencrypt.sh
@@ -55,7 +55,7 @@ sign_domain() {
     challenge_token="$(printf '%s\n' "${response}" | grep -Eo '"challenges":[^\[]*\[[^]]*]' | sed 's/{/\n{/g' | grep 'http-01' | grep -Eo '"token":\s*"[^"]*"' | cut -d'"' -f4 | sed 's/[^A-Za-z0-9_\-]/_/g')"
     challenge_uri="$(printf '%s\n' "${response}" | grep -Eo '"challenges":[^\[]*\[[^]]*]' | sed 's/{/\n{/g' | grep 'http-01' | grep -Eo '"uri":\s*"[^"]*"' | cut -d'"' -f4)"
 
-    if [ "${challenge_token}" = "" ] || [ "${challenge_uri}" = "" ]; then
+    if [ -z "${challenge_token}" ] || [ -z "${challenge_uri}" ]; then
       echo "  + Error: Can't retrieve challenges (${response})"
       exit 1
     fi