updating icon cache only on first install

diff --git a/debian/postinst b/debian/postinst
index 887ea06..29e1a27 100755 (executable)
--- a/debian/postinst
+++ b/debian/postinst
@@ -6,6 +6,9 @@
 ## ----------------------------------------------------------------------
 set -e
 
-gtk-update-icon-cache -f /usr/share/icons/hicolor
+oldversion="$2"
+if [ -z "$oldversion" ]; then
+  gtk-update-icon-cache -f /usr/share/icons/hicolor
+fi
 
 exit 0