# reth debug build-block Debug block building ```bash $ reth debug build-block --help Usage: reth debug build-block [OPTIONS] --prev-randao --timestamp --suggested-fee-recipient Options: --instance Add a new instance of a node. Configures the ports of the node to avoid conflicts with the defaults. This is useful for running multiple nodes on the same machine. Max number of instances is 200. It is chosen in a way so that it's not possible to have port numbers that conflict with each other. Changes to the following port numbers: - `DISCOVERY_PORT`: default + `instance` - 1 - `AUTH_PORT`: default + `instance` * 100 - 100 - `HTTP_RPC_PORT`: default - `instance` + 1 - `WS_RPC_PORT`: default + `instance` * 2 - 2 [default: 1] -h, --help Print help (see a summary with '-h') Datadir: --datadir The path to the data dir for all reth files and subdirectories. Defaults to the OS-specific data directory: - Linux: `$XDG_DATA_HOME/reth/` or `$HOME/.local/share/reth/` - Windows: `{FOLDERID_RoamingAppData}/reth/` - macOS: `$HOME/Library/Application Support/reth/` [default: default] --datadir.static_files The absolute path to store static files in. --config The path to the configuration file to use --chain The chain this node is running. Possible values are either a built-in chain or the path to a chain specification file. Built-in chains: mainnet, sepolia, holesky, dev [default: mainnet] Database: --db.log-level Database logging level. Levels higher than "notice" require a debug build Possible values: - fatal: Enables logging for critical conditions, i.e. assertion failures - error: Enables logging for error conditions - warn: Enables logging for warning conditions - notice: Enables logging for normal but significant condition - verbose: Enables logging for verbose informational - debug: Enables logging for debug-level messages - trace: Enables logging for trace debug-level messages - extra: Enables logging for extra debug-level messages --db.exclusive Open environment in exclusive/monopolistic mode. Makes it possible to open a database on an NFS volume [possible values: true, false] --trusted-setup-file Overrides the KZG trusted setup by reading from the supplied file --parent-beacon-block-root --prev-randao --timestamp --suggested-fee-recipient --transactions Array of transactions. NOTE: 4844 transactions must be provided in the same order as they appear in the blobs bundle --blobs-bundle-path Path to the file that contains a corresponding blobs bundle Logging: --log.stdout.format The format to use for logs written to stdout [default: terminal] Possible values: - json: Represents JSON formatting for logs. This format outputs log records as JSON objects, making it suitable for structured logging - log-fmt: Represents logfmt (key=value) formatting for logs. This format is concise and human-readable, typically used in command-line applications - terminal: Represents terminal-friendly formatting for logs --log.stdout.filter The filter to use for logs written to stdout [default: ] --log.file.format The format to use for logs written to the log file [default: terminal] Possible values: - json: Represents JSON formatting for logs. This format outputs log records as JSON objects, making it suitable for structured logging - log-fmt: Represents logfmt (key=value) formatting for logs. This format is concise and human-readable, typically used in command-line applications - terminal: Represents terminal-friendly formatting for logs --log.file.filter The filter to use for logs written to the log file [default: debug] --log.file.directory The path to put log files in [default: /logs] --log.file.max-size The maximum size (in MB) of one log file [default: 200] --log.file.max-files The maximum amount of log files that will be stored. If set to 0, background file logging is disabled [default: 5] --log.journald Write logs to journald --log.journald.filter The filter to use for logs written to journald [default: error] --color Sets whether or not the formatter emits ANSI terminal escape codes for colors and other text formatting [default: always] Possible values: - always: Colors on - auto: Colors on - never: Colors off Display: -v, --verbosity... Set the minimum log level. -v Errors -vv Warnings -vvv Info -vvvv Debug -vvvvv Traces (warning: very verbose!) -q, --quiet Silence all log output ```