diff --git a/install-and-chroot.sh b/install-and-chroot.sh
index 7e4278d..3baf32f 100755
--- a/install-and-chroot.sh
+++ b/install-and-chroot.sh
@@ -3,6 +3,12 @@
 alpine_install=${INSTALL:-'alpine-chroot-install'}
 alpine_directory=${DIR:-'/alpine'}
 
+# Tests
+DIR="${alpine_directory}"
+if ! [[ $DIR == /* ]]; then
+  echo "DIR is not an absolute URL. It should start with a '/'" && exit 1
+fi
+
 # DL alpine install script
 if ! test -f "$alpine_install"; then
   wget https://raw.githubusercontent.com/alpinelinux/alpine-chroot-install/v0.9.0/alpine-chroot-install -O "$alpine_install" \
@@ -12,12 +18,14 @@ if ! test -f "$alpine_install"; then
 fi
 
 # Install Alpine
-if ! test -d "$alpine_directory"; then
-  sudo sh ./$alpine_install -d $alpine_directory -p build-base -p git -p zsh -p lua-filesystem -p luarocks5.1 -p lua-toml -p moonscript -p abuild -p lua-argparse || exit 1
+if ! test -d "$DIR"; then
+  sudo sh ./$alpine_install -d $DIR -p build-base -p git -p zsh -p lua-filesystem -p luarocks5.1 -p lua-toml -p moonscript -p abuild -p lua-argparse || exit 1
 fi
 
 # Set rc_sys="prefix" to not disturb systemd on current system
-sudo sed -e 's/#rc_sys=""/rc_sys="prefix"/g' -i "$alpine_directory/etc/rc.conf"
+sudo sed -e 's/#rc_sys=""/rc_sys="prefix"/g' -i "$DIR/etc/rc.conf"
 
 # Launch chroot
-sh $alpine_directory/enter-chroot ./build
+sh $DIR/enter-chroot ./build
+
+exit 0