Running Bitcoin
There are two variations of the official bitcoin program available; one with a graphical user interface (usually referred to as just “Bitcoin”), and a 'headless' version (called bitcoind). They are completely compatible with each other, and take the same command-line arguments, read the same configuration file, and read and write the same data files. You can run one copy of either Bitcoin or bitcoind on your system at a time (if you accidently try to launch another, the copy will let you know that Bitcoin or bitcoind is already running and will exit).