The bitcoin daemon on the offline computer is used solely to sign transactions and runs without a blockchain. Thus even a low-powered computer such as a Raspberry Pi or an old netbook can serve nicely as your offline machine.
The bitcoin daemon on the online computer requires a complete and up-to-date blockchain for tracking addresses. Since its work is more CPU and disk intensive, a more powerful computer is required here. You’ll also need plenty of free disk space for the growing blockchain (~265GB at the time of writing).
Two blockchain operations are especially resource-intensive: synchronizing the blockchain and importing existing addresses with balances. If you synchronize often (once a week, for example) and take care to import your addresses before spending into them, then it’s possible to get by with a more low-powered computer as your online machine.
Bitcoin Core:
Go to the Bitcoin Core download page (here or here). Choose the 32-bit or 64-bit versions appropriate for your online and offline computers. Windows users should choose the executable installer.
Bitcoin ABC (optional):
If you wish to transact BCH (Bcash), then download the appropriate Bitcoin ABC binary for your system as well. Windows users should choose the executable installer. Consider the Bitcoin ABC binaries untrusted software. The author of the MMGen project makes no guarantees regarding their safety or reliability.
Litecoin (optional):
Go to the Litecoin Core download page. Choose the 32-bit or 64-bit versions appropriate for your online and offline computers. Windows users should choose the executable installer.
Bitcoin Core:
Windows: Run the Windows installer with the default settings. At the end of the installation process, uncheck the Run box to prevent the client from starting. Add
C:\Program Files\Bitcoin\daemon
to your path.
Linux: Unpack the archive and copy thebitcoind
andbitcoin-cli
binaries to/usr/local/bin
.Bitcoin ABC (optional):
Windows: Run the Windows installer with the default settings. At the end of the installation process, uncheck the Run box to prevent the client from starting. Add
C:\Program Files\Bitcoin-abc\daemon
to your path. Rename the filebitcoind
in that folder tobitcoind-abc
andbitcoin-cli
tobitcoin-cli-abc
.
Linux: Unpack the archive, renamebitcoind
tobitcoind-abc
and copy it to/usr/local/bin
.Litecoin (optional):
Windows: Run the Windows installer with the default settings. At the end of the installation process, uncheck the Run box to prevent the client from starting. Add
C:\Program Files\Litecoin\daemon
to your path.
Linux: Unpack the archive and copy thelitecoind
andlitecoin-cli
binaries to/usr/local/bin
.
Windows:
In the Windows command-line environment processes don’t fork to run in the background, so to run multiple daemons simultaneously you must start each one in a separate terminal window. Start your daemons like this:
# Bitcoin Core:
$ bitcoind
# ABC:
$ mkdir $APPDATA/Bitcoin_ABC
$ bitcoind-abc --listen=0 --rpcport=8442 --datadir=$APPDATA/Bitcoin_ABC --usecashaddr=0
# Litecoin
$ litecoind
Note that the
--listen=0
argument is required only when running Core and ABC simultaneously.Linux:
Linux users start their daemons like this:
# Bitcoin Core:
$ bitcoind --daemon
# ABC:
$ mkdir ~/.bitcoin-abc
$ bitcoind-abc --daemon --listen=0 --rpcport=8442 --datadir=$HOME/.bitcoin-abc --usecashaddr=0
# Litecoin:
$ litecoind --daemon
Communicate with your daemons like this:
# Core:
$ bitcoin-cli help
# ABC:
$ bitcoin-cli-abc --rpcport=8442 help
# Litecoin:
$ litecoin-cli help
Warning: If you’re using an existing Bitcoin or Litecoin installation, move your wallet.dat out of harm’s way before starting the daemon. The new wallet now created will be used as your tracking wallet.
If you’re connected to the Internet, the daemon(s) will begin downloading and verifying the blockchain. This can take from several hours to several days depending on the speed of your computer, the size of the blockchain(s) in question and your Internet connection. You can speed up your initial block download enormously by adding the
-assumevalid
option, followed by a recent block hash, to the command line. Recent block hashes can be found on any blockchain explorer site.For the offline daemons you may add the options
-maxconnections=0 -listen=0
to the command line. Note that offline daemons start very quickly, since they have a blockchain consisting of one block, and use practically no CPU power once running.