remove redundant $ inside arithmetic contexts

install.sh

@@ -20,7 +20,7 @@ function download_files() {
     shift
     curl -fsSL --output-dir "$WORK_DIR/" --remote-name "$API_ENDPOINT/raw/$path$query_params"
     rc=$?
-    if (( $rc != 0 )); then
+    if (( rc != 0 )); then
       return $rc
     fi
   done
@@ -42,7 +42,7 @@ chmod o= "$WORK_DIR/config.example"
 
 "$WORK_DIR/pbc" install
 rc=$?
-if (( $rc != 0 )); then
+if (( rc != 0 )); then
   echo "Error installing pbc requirements!" >&2
   exit $rc
 fi

pbc

@@ -80,7 +80,7 @@ function apt_get_install() {
   echo "Installing $package using package manager ..."
   DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends "$package" >/dev/null
   local rc=$?
-  (( $rc != 0 )) && echo "Error installing package!" >&2
+  (( rc != 0 )) && echo "Error installing package!" >&2
   return $rc
 }