archivemount [ edit files inside a tar package ]

[root@f20 ~]# tar czf /tmp/ul137194.tar.gz -C / /etc/passwd /etc/group /etc/shells
[root@f20 ~]# mkdir /tmp/ul137194
[root@f20 ~]# archivemount /tmp/ul137194.tar.gz /tmp/ul137194
[root@f20 ~]# find /tmp/ul137194
[root@f20 ~]# rm /tmp/ul137194/etc/shells
[root@f20 ~]# echo nogroups > /tmp/ul137194/etc/group
[root@f20 ~]# umount /tmp/ul137194
[root@f20 ~]# tar xzf /tmp/ul137194.tar.gz -C /tmp/ul137194
[root@f20 ~]# find /tmp/ul137194
[root@f20 ~]# cat /tmp/ul137194/etc/group