## Install Bitcoind and other supported coin daemons

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.

### <a name='a_d'>Download:</a>

> **Bitcoin Core:**

>> Go to the Bitcoin Core download page ([here][00] or [here][01]).  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][abc] 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][lc].  Choose the 32-bit or 64-bit
>> versions appropriate for your online and offline computers.  Windows users
>> should choose the executable installer.

### <a name='a_i'>Install (both online and offline computers):</a>

> **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][05].  
>> **Linux:** Unpack the archive and copy the `bitcoind` and `bitcoin-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][05].
>> Rename the file `bitcoind` in that folder to `bitcoind-abc` and
>> `bitcoin-cli` to `bitcoin-cli-abc`.  
>> **Linux:** Unpack the archive, rename `bitcoind` to `bitcoind-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][05].  
>> **Linux:** Unpack the archive and copy the `litecoind` and
>> `litecoin-cli` binaries to `/usr/local/bin`.

### <a name='a_r'>Run (both online and offline computers):</a>

> **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.

[00]: https://bitcoin.org/bin/
[01]: https://bitcoincore.org/bin/
[bd]: https://bitcoin.org/bin/blockchain/
[05]: Editing-the-user-path-in-Windows
[abc]: https://download.bitcoinabc.org/
[lc]: https://download.litecoin.org/litecoin-0.17.1/