Generate address (for receiving) on GNU/Linux without Bitcoin client?
I recommend simply using vanitygen like this:

vanitygen -1 1


This will generate a small number of addresses that you can use, as well as their private keys.

vanitygen is trivial to install on any POSIX system and is proven to work.

Alternatively, you can try bitcoin-bash-tools. Source that from your .bashrc or simply run it, then you can create a new keypair with newBitcoinKey.