The configuration file is used by `bitcoind`, `bitcoin-qt` and `bitcoin-cli`.
All command-line options (except for `-?`, `-help`, `-version` and `-conf`) may be specified in a configuration file, and all configuration file options (except for `includeconf`) may also be specified on the command line. Command-line options override values set in the configuration file and configuration file options override values set in the GUI.
## Configuration File Format
The configuration file is a plain text file and consists of `option=value` entries, one per line. Leading and trailing whitespaces are removed.
In contrast to the command-line usage:
- an option must be specified without leading `-`;
- a value of the given option is mandatory; e.g., `testnet=1` (for chain selection options), `noconnect=1` (for negated options).
### Blank lines
Blank lines are allowed and ignored by the parser.
### Comments
A comment starts with a number sign (`#`) and extends to the end of the line. All comments are ignored by the parser.
Comments may appear in two ways:
- on their own on an otherwise empty line (_preferable_);
- after an `option=value` entry.
### Network specific options
Network specific options can be:
- placed into sections with headers `[main]` (not `[mainnet]`), `[test]` (not `[testnet]`) or `[regtest]`;
- prefixed with a chain name; e.g., `regtest.maxmempool=100`.
The configuration file is not automatically created; you can create it using your favorite text editor. By default, the configuration file name is `bitcoin.conf` and it is located in the Bitcoin data directory, but both the Bitcoin data directory and the configuration file path may be changed using the `-datadir` and `-conf` command-line options.
The `includeconf=<file>` option in the `bitcoin.conf` file can be used to include additional configuration files.
