Bitcoin command line parameters

Command-line arguments

These commands are accurate as of Bitcoin Core version v0.12.0rc1.

Command Description
-? This help message
-alerts Receive and display P2P network alerts (default: 1)
-alertnotify=<cmd> Execute command when a relevant alert is received or we see a really long fork (%s in cmd is replaced by message)
-blocknotify=<cmd> Execute command when the best block changes (%s in cmd is replaced by block hash)
-checkblocks=<n> How many blocks to check at startup (default: 288, 0 = all)
-checklevel=<n> How thorough the block verification of -checkblocks is (0-4, default: 3)
-conf=<file> Specify configuration file (default: bitcoin.conf)
-datadir=<dir> Specify data directory
-dbcache=<n> Set database cache size in megabytes (4 to 16384, default: 100)
-loadblock=<file> Imports blocks from external blk000??.dat file on startup
-maxorphantx=<n> Keep at most <n> unconnectable transactions in memory (default: 100)
-maxmempool=<n> Keep the transaction memory pool below <n> megabytes (default: 300)
-mempoolexpiry=<n> Do not keep transactions in the mempool longer than <n> hours (default: 72)
-par=<n> Set the number of script verification threads (-2 to 16, 0 = auto, <0 = leave that many cores free, default: 0)
-prune=<n> Reduce storage requirements by pruning (deleting) old blocks. This mode is incompatible with -txindex and -rescan. Warning: Reverting this setting requires re-downloading the entire blockchain. (default: 0 = disable pruning blocks, >550 = target size in MiB to use for block files)
-reindex Rebuild block chain index from current blk000??.dat files on startup
-txindex Maintain a full transaction index, used by the getrawtransaction rpc call (default: 0)
Connection options:
-addnode=<ip> Add a node to connect to and attempt to keep the connection open
-banscore=<n> Threshold for disconnecting misbehaving peers (default: 100)
-bantime=<n> Number of seconds to keep misbehaving peers from reconnecting (default: 86400)
-bind=<addr> Bind to given address and always listen on it. Use [host]:port notation for IPv6
-connect=<ip> Connect only to the specified node(s)
-discover Discover own IP addresses (default: 1 when listening and no -externalip or -proxy)
-dns Allow DNS lookups for -addnode, -seednode and -connect (default: 1)
-dnsseed Query for peer addresses via DNS lookup, if low on addresses (default: 1 unless -connect)
-externalip=<ip> Specify your own public address
-forcednsseed Always query for peer addresses via DNS lookup (default: 0)
-listen Accept connections from outside (default: 1 if no -proxy or -connect)
-listenonion Automatically create Tor hidden service (default: 1)
-maxconnections=<n> Maintain at most <n> connections to peers (default: 125)
-maxreceivebuffer=<n> Maximum per-connection receive buffer, <n>*1000 bytes (default: 5000)
-maxsendbuffer=<n> Maximum per-connection send buffer, <n>*1000 bytes (default: 1000)
-onion=<ip:port> Use separate SOCKS5 proxy to reach peers via Tor hidden services (default: -proxy)
-onlynet=<net> Only connect to nodes in network <net> (ipv4, ipv6 or onion)
-permitbaremultisig Relay non-P2SH multisig (default: 1)
-peerbloomfilters Support filtering of blocks and transaction with bloom filters (default: 1)
-port=<port> Listen for connections on <port> (default: 8333 or testnet: 18333)
-proxy=<ip:port> Connect through SOCKS5 proxy
-proxyrandomize Randomize credentials for every proxy connection. This enables Tor stream isolation (default: 1)
-seednode=<ip> Connect to a node to retrieve peer addresses, and disconnect
-timeout=<n> Specify connection timeout in milliseconds (minimum: 1, default: 5000)
-torcontrol=<ip>:<port> Tor control port to use if onion listening enabled (default:
-torpassword=<pass> Tor control port password (default: empty)
-upnp Use UPnP to map the listening port (default: 0)
-whitebind=<addr> Bind to given address and whitelist peers connecting to it. Use [host]:port notation for IPv6
-whitelist=<netmask> Whitelist peers connecting from the given netmask or IP address. Can be specified multiple times. Whitelisted peers cannot be DoS banned and their transactions are always relayed, even if they are already in the mempool, useful e.g. for a gateway
-whitelistalwaysrelay Always relay transactions received from whitelisted peers (default: 1)
-maxuploadtarget=<n> Tries to keep outbound traffic under the given target (in MiB per 24h), 0 = no limit (default: 0)
Wallet options:
-disablewallet Do not load the wallet and disable wallet RPC calls
-keypool=<n> Set key pool size to <n> (default: 100)
-fallbackfee=<amt> A fee rate (in BTC/kB) that will be used when fee estimation has insufficient data (default: 0.0002)
-mintxfee=<amt> Fees (in BTC/kB) smaller than this are considered zero fee for transaction creation (default: 0.00001)
-paytxfee=<amt> Fee (in BTC/kB) to add to transactions you send (default: 0.00)
-rescan Rescan the block chain for missing wallet transactions on startup
-salvagewallet Attempt to recover private keys from a corrupt wallet.dat on startup
-sendfreetransactions Send transactions as zero-fee transactions if possible (default: 0)
-spendzeroconfchange Spend unconfirmed change when sending transactions (default: 1)
-txconfirmtarget=<n> If paytxfee is not set, include enough fee so transactions begin confirmation on average within n blocks (default: 2)
-maxtxfee=<amt> Maximum total fees (in BTC) to use in a single wallet transaction; setting this too low may abort large transactions (default: 0.10)
-upgradewallet Upgrade wallet to latest format on startup
-wallet=<file> Specify wallet file (within data directory) (default: wallet.dat)
-walletbroadcast Make the wallet broadcast transactions (default: 1)
-walletnotify=<cmd> Execute command when a wallet transaction changes (%s in cmd is replaced by TxID)
-zapwallettxes=<mode> Delete all wallet transactions and only recover those parts of the blockchain through -rescan on startup (1 = keep tx meta data e.g. account owner and payment request information, 2 = drop tx meta data)
Debugging/Testing options:
-debug=<category> Output debugging information (default: 0, supplying <category> is optional). If <category> is not supplied or if <category> = 1, output all debugging information.<category> can be: addrman, alert, bench, coindb, db, lock, rand, rpc, selectcoins, mempool, mempoolrej, net, proxy, prune, http, libevent, tor, zmq, qt.
-gen Generate coins (default: 0)
-genproclimit=<n> Set the number of threads for coin generation if enabled (-1 = all cores, default: 1)
-help-debug Show all debugging options (usage: –help -help-debug)
-logips Include IP addresses in debug output (default: 0)
-logtimestamps Prepend debug output with timestamp (default: 1)
-printtoconsole Send trace/debug info to console instead of debug.log file
-shrinkdebugfile Shrink debug.log file on client startup (default: 1 when no -debug)
Chain selection options:
-testnet Use the test chain
Node relay options:
-minrelaytxfee=<amt> Fees (in BTC/kB) smaller than this are considered zero fee for relaying, mining and transaction creation (default: 0.00001)
-limitfreerelay=<n> Rate-limit free transactions to <n>*1000 bytes per minute (default: 15)
-bytespersigop Minimum bytes per sigop in transactions we relay and mine (default: 20)
-datacarrier Relay and mine data carrier transactions (default: 1)
-datacarriersize Maximum size of data in data carrier transactions we relay and mine (default: 83)
Block creation options:
-blockminsize=<n> Set minimum block size in bytes (default: 0)
-blockmaxsize=<n> Set maximum block size in bytes (default: 750000)
-blockprioritysize=<n> Set maximum size of high-priority/low-fee transactions in bytes (default: 0)
RPC server options:
-server Accept command line and JSON-RPC commands
-rest Accept public REST requests (default: 0)
-rpcbind=<addr> Bind to given address to listen for JSON-RPC connections. Use [host]:port notation for IPv6. This option can be specified multiple times (default: bind to all interfaces)
-rpcuser=<user> Username for JSON-RPC connections
-rpcpassword=<pw> Password for JSON-RPC connections
-rpcauth=<userpw> Username and hashed password for JSON-RPC connections. The field <userpw> comes in the format: <USERNAME>:<SALT>$<HASH>. A canonical python script is included in share/rpcuser. This option can be specified multiple times
-rpcport=<port> Listen for JSON-RPC connections on <port> (default: 8332 or testnet: 18332)
-rpcallowip=<ip> Allow JSON-RPC connections from specified source. Valid for <ip> are a single IP (e.g., a network/netmask (e.g. or a network/CIDR (e.g. This option can be specified multiple times
-rpcthreads=<n> Set the number of threads to service RPC calls (default: 4)
UI Options:
-choosedatadir Choose data directory on startup (default: 0)
-lang=<lang> Set language, for example “de_DE” (default: system locale)
-min Start minimized
-rootcertificates=<file> Set SSL root certificates for payment request (default: -system-)
-splash Show splash screen on startup (default: 1)
-resetguisettings Reset all settings changes made over the GUI

Many of the boolean options can also be set to off by specifying them with a “no” prefix: e.g. -nodnseed.