diff --git a/README.md b/README.md
index 7280eef..66b15e4 100644
--- a/README.md
+++ b/README.md
@@ -22,7 +22,7 @@ But you can change destination directory if needed:
 
 ```bash
 chmod +x ./install-and-chroot.sh
-DIR="/my_alpine_chroot" ./install-and-chroot.sh
+DIRPATH="/my_alpine_chroot" ./install-and-chroot.sh
 ```
 
 and then:
@@ -31,6 +31,8 @@ and then:
 /my_alpine_chroot/enter-chroot
 ```
 
+Pay attention: DIRPATH should be an absolute path.
+
 # TODO
 
   * adapt script to install yunoconfig dependencies (alpine-chroot-install -p)
diff --git a/install-and-chroot.sh b/install-and-chroot.sh
index 3baf32f..e3d7994 100755
--- a/install-and-chroot.sh
+++ b/install-and-chroot.sh
@@ -1,25 +1,24 @@
 #!/usr/bin/env sh
 
-alpine_install=${INSTALL:-'alpine-chroot-install'}
-alpine_directory=${DIR:-'/alpine'}
+SCRIPT=${SCRIPTNAME:-'alpine-chroot-install'}
+DIR=${DIRPATH:-'/alpine'}
 
 # Tests
-DIR="${alpine_directory}"
 if ! [[ $DIR == /* ]]; then
-  echo "DIR is not an absolute URL. It should start with a '/'" && exit 1
+  echo "DIRPATH 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" \
-    && echo 'e5dfbbdc0c4b3363b99334510976c86bfa6cb251  alpine-chroot-install' | sha1sum -c \
+if ! test -f "$SCRIPT"; then
+  wget https://raw.githubusercontent.com/alpinelinux/alpine-chroot-install/v0.9.0/alpine-chroot-install -O "$SCRIPT" \
+    && echo "e5dfbbdc0c4b3363b99334510976c86bfa6cb251  ${SCRIPT}" | sha1sum -c \
       || exit 1
-  chmod +x "$alpine_install"
+  chmod +x "$SCRIPT"
 fi
 
 # Install Alpine
 if ! test -d "$DIR"; then
-  sudo sh ./$alpine_install -d $DIR -p build-base -p git -p zsh -p lua-filesystem -p luarocks5.1 -p lua-toml -p moonscript -p abuild -p lua-argparse || exit 1
+  sudo sh ./$SCRIPT -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