diff --git a/scripts/fetch-language-data.sh b/scripts/fetch-language-data.sh
index 9b93e54..65b8e8a 100755
--- a/scripts/fetch-language-data.sh
+++ b/scripts/fetch-language-data.sh
@@ -1,32 +1,33 @@
 #!/bin/bash
 
-BASEDIR=$(dirname "$0")
-BASEDIR="$BASEDIR/.."
+set -o errexit -o nounset -o pipefail
 
+BASEDIR=$(dirname "$(dirname "$(readlink -f "$0")")")
 DEST="$BASEDIR/src/"
 CLONEDIR="$BASEDIR/vendor/language-data"
-
 UPSTREAM="https://github.com/wikimedia/language-data.git"
 
 echo "Getting latest language-data from $UPSTREAM"
 
-if [ -d "$CLONEDIR" ]; then
-	pushd "$CLONEDIR"
+if [ -d "$CLONEDIR" ]
+then (
+	cd "$CLONEDIR"
 	git pull
-	popd
-else
+) else
 	git clone "$UPSTREAM" "$CLONEDIR"
 fi
-if [ -d "$BASEDIR"/node_modules/browserify ];then
+
+if [ -d "$BASEDIR"/node_modules/browserify ]
+then
 	echo "browserify already installed"
-else
-    echo "Installing browserify"
+else (
+	echo "Installing browserify"
+	cd "$BASEDIR";
 	npm install browserify
-fi
+) fi
 
 echo "Transforming language-data"
 
-"$BASEDIR"/node_modules/browserify/bin/cmd.js "$CLONEDIR"/language-data.json -t "$BASEDIR"/scripts/transform.js  -o "$DEST"/jquery.uls.data.js
+"$BASEDIR"/node_modules/browserify/bin/cmd.js "$CLONEDIR"/language-data.json -t "$BASEDIR"/scripts/transform.js -o "$DEST"/jquery.uls.data.js
 
 echo "language-data wrote to $DEST/jquery.uls.data.js"
-echo "Done."