Forwarding error to std output in bash script now

scripts/build.sh

@@ -4,7 +4,7 @@
 necessary_packages=("pdflatex")
 
 for package in ${necessary_packages}; do
-    if ! [dpkg -l ${package} > /dev/null]; then
+    if ! [dpkg -l ${package} > /dev/null 2>&1]; then
         echo "Error: ${package} is not installed."
         exit 1
     fi