Fix linting issues in scripts

.local/bin/package-alert

@@ -5,17 +5,17 @@ WATCHLIST=~/.local/share/package-alert/watchlist
 agg_results=""
 
 if [ -f "${WATCHLIST}" ]; then
-    for pattern in $(cat "${WATCHLIST}"); do
+    while read -r pattern; do
         pat_results=$(apt-cache search --names-only "${pattern}")
-        if [ ! -z "${pat_results}" ]; then
+        if [ -n "${pat_results}" ]; then
             agg_results="${agg_results:+${agg_results}
 }Packages matching \"${pattern}\":
 ${pat_results}
 "
         fi
-    done
+    done < "${WATCHLIST}"
 fi
 
-if [ ! -z "${agg_results}" ]; then
+if [ -n "${agg_results}" ]; then
     printf '%s' "${agg_results}" | /usr/sbin/sendmail "${USER}"
 fi