diff --git a/helpers/config b/helpers/config
index 1f0c8cb..229efc4 100755
--- a/helpers/config
+++ b/helpers/config
@@ -19,6 +19,8 @@
 #
 
 set -e
+set -o pipefail
+
 export LANG=C LC_TIME=C
 PACKAGE=$(echo $0 |/bin/sed s/make-//g)
 
@@ -130,7 +132,7 @@ if [ "1$SIGNKEY" != "1" ] ; then
 else
   if grep -q "BEGIN PGP SIGNATURE" *.dsc; then
     KEY=$(gpgv --keyring ${LOCAL_APT}/etc/trusted.gpg *.dsc 2>&1 | grep "key ID" | sed 's/.*key ID //' || true)
-    [ $KEY -z ] && KEY=$(gpgv --keyring ${LOCAL_APT}/etc/trusted.gpg *.dsc 2>&1 | egrep ".SA key" | sed 's/.*.SA key //' || true)
+    [ -z "$KEY" ] && KEY=$(gpgv --keyring ${LOCAL_APT}/etc/trusted.gpg *.dsc 2>&1 | egrep ".SA key" | sed 's/.*.SA key //' || true)
     apt-key --keyring ${LOCAL_APT}/etc/trusted.gpg adv --recv-keys --keyserver keyserver.ubuntu.com $KEY > /dev/null
     gpgv --keyring ${LOCAL_APT}/etc/trusted.gpg *.dsc
   else