These days I’m playing with Sabayon MCS, a live linux distro with MailWare Collaboration.

A live distro is usually an .iso containing a linux hierarchy tree in a compressed squashfs. I was modifying that fs and before committing the changes to the Sabayon repo, I was trying to test the results on a “mock” iso I created with a nice tool named mhddfs.

It’s simply a virtual filesystem made of layered directories. Let’s play with it!
Install mhddfs
# sudo apt-get install mhddfs
Populate a tree
# pushd /tmp;
# mkdir -p a{1,2}/b/c/d{1,2} newfs
# echo a1 > a1/f
# echo a2 > a2/f
# touch a1/b/c/d1/f1
# touch a2/b/c/d2/f2

Mount the new fs on /tmp/newfs
# mhddfs /tmp/a1 /tmp/a2 /tmp/newfs

See what’s happening (exercise for the reader):
# find /tmp/newfs

# cat /tmp/newfs/f