Newbie question: How to connect to Oracle db from linux command line

I had experience with mysql before, but know completely nothing about Oracle DB.

Recently, I'm assigned to add a simple feature to an existing system.
Albeit simple, I need to connect to the db and get some knowledge about the existing database. But I simply don't know how to do that.
I have ssh access with su privilege on a debian remote machine that can connect to the database server.

Below is the java code I received that should be db accessing part. I think it might help you understand my problem (I'm a really a newbie):

        String url = "jdbc:oracle:thin:@aaa.bbb.ccc.ddd:port/price";
        Properties info = new Properties();
        info.setProperty("user", "username");
        info.setProperty("password", "password");

So, how can I connect to Oracle db from linux command line?