Index: /trunk/renametag
===================================================================
--- /trunk/renametag	(revision 18)
+++ /trunk/renametag	(revision 18)
@@ -0,0 +1,11 @@
+#!/bin/bash
+
+OLD_TAG=$1
+NEW_TAG=$2
+FLAC=$3
+
+# to change the name of a FLAC tag
+# e.g., from MBZ_DISCID to MUSICBRAINZ_DISCID
+metaflac --show-tag "$OLD_TAG" "$FLAC" \
+    | sed "s/^$OLD_TAG=/$NEW_TAG=/" \
+    | metaflac --remove-tag "$OLD_TAG" --import-tags-from - "$FLAC"