restore/recover backed up wallet

[roberto32]

I use linux, my wallet was in chown-ed folder but as I install second distro I eventually removed  filesystem parititon of the old distro. After that my wallet (which is in another parition which remain unchanged -no formatting) has different adress, cleared history, no coins.. but fortunately I backed it up before. So my question is how to restore the old wallet?? I read somewhere that I've to name the back wallet.dat and place it somewhere in bitcoin folder but where??

[runlinux]

If you have the old backup, I think it goes /home/<username>/.bitcoin/