Restore a wallet from an external drive?
To avoid any problem,in your source computer backup your private keys 

bitcoind dumpprivkey 

to answer your question, By default Bitcoin will put its data here:

~/.bitcoin/

I think the wallet is located in a file wallet.dat(https://en.bitcoin.it/wiki/Data_directory#Linux), so if you copy it, it will works.

fore a best security level, encrypt your wallet with a paraphrase before backaping it.