Skip downloading existing pictures

.local/bin/get-nasa-apod

@@ -21,6 +21,11 @@ extension="${picture_url##*.}"
 filename="${picture_date}.${extension}"
 outfile="${WALLPAPERS}/${filename}"
 
+if [ -f "${outfile}" ]; then
+    echo "Target file already exists"
+    exit 0
+fi
+
 tempfile="$(mktemp)"
 curl \
     --location \