diff --git a/Dockerfile b/Dockerfile
index ef91bf2..74e1914 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -10,11 +10,11 @@ ARG NO_PROXY
 COPY sc.crt /tmp/sc.crt
 RUN echo $OS_DISTRIBUTION
 RUN echo $PROXY_CERT_PATH
-RUN if [ "${OS_DISTRIBUTION}" = "ubuntu" ] && [ ! -z ${PROXY_CERT_PATH} ]; then \
+RUN if [ "${OS_DISTRIBUTION}" = "ubuntu" ] && [ ${PROXY_CERT_PATH} != "" ]; then \
     cp /tmp/sc.crt /etc/ssl/certs && \
     update-ca-certificates; \
     fi 
-RUN if [ "${OS_DISTRIBUTION}" = "opensuse" ] && [ ! -z ${PROXY_CERT_PATH} ]; then \
+RUN if [ "${OS_DISTRIBUTION}" = "opensuse" ] && [ ${PROXY_CERT_PATH} != "" ]; then \
     cp /tmp/sc.crt /usr/share/pki/trust/anchors && \
     update-ca-certificates; \
     fi