-/dev/external /mnt/external auto users,noauto,exec,rw,uid=grml,gid=grml 0 0
-/dev/external1 /mnt/external1 auto users,noauto,exec,rw,uid=grml,gid=grml 0 0
+/dev/external /mnt/external auto users,noauto,exec,rw,uid=$USERNAME,gid=$USERNAME 0 0
+/dev/external1 /mnt/external1 auto users,noauto,exec,rw,uid=$USERNAME,gid=$USERNAME 0 0