diff --git a/tools/sys_base_install.sh b/tools/sys_base_install.sh
index 6e87523..7f039ee 100755
--- a/tools/sys_base_install.sh
+++ b/tools/sys_base_install.sh
@@ -11,10 +11,10 @@ export GJ_DEVENV="local_aptproxy"
 export GJ_SHELL="bash"
 
 function set_apt_proxy {
-	if [ "$GJ_DEVENV" == "local_aptproxy" ]; then
+	if [[ "$GJ_DEVENV" == "local_aptproxy" ]]; then
 		echo "Setting apt-proxy: srvths"
 		printf 'Acquire::http { Proxy "http://192.168.188.110:3142"; };\nAcquire::https { Proxy "https://"; };\n' > /etc/apt/apt.conf.d/02proxy
-	elif [ "$GJ_DEVENV" == "hetzner_server" ]; then
+	elif [[ "$GJ_DEVENV" == "hetzner_server" ]]; then
 		echo "Setting apt-mirror: hetzner mirror"
 		echo 'deb ftp://mirror.hetzner.de/debian/packages wheezy main contrib non-free' > /etc/apt/sources.list.d/hetzner.list
 		echo 'deb ftp://mirror.hetzner.de/debian/security wheezy/updates main contrib non-free' >> /etc/apt/sources.list.d/hetzner.list