g_spawning three processes: one after another only when...

[Colossus <colossus 3000 it>]

Hi,

I need to launch these three processes:
1) bzip2 -dc archive.tar.bz2 > /tmp/foo.tar
2) tar --delete -vf /tmp/foo.tar file_to_del
3) bzip2 -c /tmp/foo.tar > archive.tar,bz2

only when each of them exits. Shall I use g_spawn_sync ?
How to code the run of all of them ?
The GUI must not freeze while these three processes are
operating on the file.

Any clue please ?
--
Colossus

Cpsed, a Linux OpenGL 3D scene editor
http://cpsed.sourceforge.net/