CLI

June 10, 2026 · View on GitHub

How to install

Running the following command will install the CLI as the binary rex.

make cli

How to run

After installing the CLI with make cli, run rex to display the help message.

> rex

Usage: rex <COMMAND>

Commands:
  address           Get either the account's address from private key, the zero address, or a random address [aliases: addr, a]
  autocomplete      Generate shell completion scripts.
  balance           Get the account's balance info. [aliases: bal, b]
  block-number      Get the current block_number. [aliases: bl]
  call              Make a call to a contract
  chain-id          Get the network's chain id.
  code              Returns code at a given address
  create-address    Compute contract address given the deployer address and nonce.
  create2-address   Compute contract address with CREATE2 opcode.
  deploy            Deploy a contract
  hash              Get either the keccak for a given input, the zero hash, the empty string, or a random hash [aliases: h]
  l2                L2 specific commands.
  nonce             Get the account's nonce. [aliases: n]
  receipt           Get the transaction's receipt. [aliases: r]
  send              Send a transaction
  sign              Sign a message with a private key
  signer
  transaction       Get the transaction's info. [aliases: tx, t]
  transfer          Transfer funds to another wallet.
  verify-signature  Verify if the signature of a message was made by an account
  encode-calldata   Encodes calldata
  decode-calldata   Decodes calldata
  help              Print this message or the help of the given subcommand(s)

Options:
  -h, --help     Print help
  -V, --version  Print version

Commands

`rex address`

Get either the account's address from private key, the zero address, or a random address

Usage: rex address [OPTIONS]

Options:
      --private-key <PRIVATE_KEY>  The private key to derive the address from. [env: PRIVATE_KEY=]
  -z, --zero                       The zero address.
  -r, --random                     A random address.
  -h, --help                       Print help

`rex autocomplete`

Generate shell completion scripts.

Usage: rex autocomplete <COMMAND>

Commands:
  generate  Generate autocomplete shell script.
  install   Generate and install autocomplete shell script.
  help      Print this message or the help of the given subcommand(s)

Options:
  -h, --help  Print help

`rex balance`

Get the account's balance info.

Usage: rex balance [OPTIONS] <ACCOUNT>

Arguments:
  <ACCOUNT>

Options:
      --token <TOKEN_ADDRESS>                       Specify the token address, the ETH is used as default.
      --eth                                         Display the balance in ETH.
      --rpc-url <RPC_URL>                           [env: RPC_URL=] [default: http://localhost:8545]
      --override-balance <ADDR:VALUE>               Override an account's balance for this call (see [State overrides](#state-overrides)).
      --override-nonce <ADDR:VALUE>                 Override an account's nonce for this call.
      --override-code <ADDR:HEX>                    Override an account's bytecode for this call.
      --override-state <ADDR:SLOT:VALUE>            Replace a storage slot for this call.
      --override-state-diff <ADDR:SLOT:VALUE>       Overlay a storage slot for this call.
      --override-move-precompile <ADDR:TARGET>      Relocate a precompile to a different address.
      --override-block-number <NUMBER>              Override the block number for this call (see [Block overrides](#block-overrides)).
      --override-block-time <TIMESTAMP>             Override the block timestamp.
      --override-block-gas-limit <GAS>              Override the block gas limit.
      --override-block-coinbase <ADDR>              Override the block coinbase (fee recipient).
      --override-block-prev-randao <HASH>           Override PREVRANDAO.
      --override-block-base-fee <VALUE>             Override the block base fee per gas.
      --override-block-blob-base-fee <VALUE>        Override the blob base fee per gas.
      --override-block-difficulty <VALUE>           Override the block difficulty.
  -h, --help                                        Print help

State and block overrides require the token form (--token); plain ETH balance reads use eth_getBalance, which does not accept overrides.

`rex block-number`

Get the current block_number.

Usage: rex block-number [OPTIONS]

Options:
      --rpc-url <RPC_URL>  [env: RPC_URL=] [default: http://localhost:8545]
  -h, --help               Print help

`rex call`

Make a call to a contract

Usage: rex call [OPTIONS] <TO> [ARGS]...

Arguments:
  <TO>
  [ARGS]...

Options:
      --calldata <CALLDATA>                         [default: ]
      --value <VALUE>                               Value to send in wei [default: 0]
      --from <FROM>
      --gas-limit <GAS_LIMIT>
      --max-fee-per-gas <MAX_FEE_PER_GAS>
      --explorer-url                                Display transaction URL in the explorer.
      --rpc-url <RPC_URL>                           [env: RPC_URL=] [default: http://localhost:8545]
      --override-balance <ADDR:VALUE>               Override an account's balance for this call (see [State overrides](#state-overrides)).
      --override-nonce <ADDR:VALUE>                 Override an account's nonce for this call.
      --override-code <ADDR:HEX>                    Override an account's bytecode for this call.
      --override-state <ADDR:SLOT:VALUE>            Replace a storage slot for this call.
      --override-state-diff <ADDR:SLOT:VALUE>       Overlay a storage slot for this call.
      --override-move-precompile <ADDR:TARGET>      Relocate a precompile to a different address.
      --override-block-number <NUMBER>              Override the block number for this call (see [Block overrides](#block-overrides)).
      --override-block-time <TIMESTAMP>             Override the block timestamp.
      --override-block-gas-limit <GAS>              Override the block gas limit.
      --override-block-coinbase <ADDR>              Override the block coinbase (fee recipient).
      --override-block-prev-randao <HASH>           Override PREVRANDAO.
      --override-block-base-fee <VALUE>             Override the block base fee per gas.
      --override-block-blob-base-fee <VALUE>        Override the blob base fee per gas.
      --override-block-difficulty <VALUE>           Override the block difficulty.
  -h, --help                                        Print help

State overrides

rex call and rex balance --token … accept a State Override Set as the 3rd eth_call parameter, matching the format documented at https://geth.ethereum.org/docs/interacting-with-geth/rpc/objects#state-override-set (also implemented in ethrex as of lambdaclass/ethrex#6660).

The node must support that parameter; if no override flags are passed, the 2-parameter form is used so older nodes keep working.

Each flag is repeatable and scoped per address:

Flag	Format	Meaning
`--override-balance`	`ADDR:VALUE`	Set the account balance (hex `0x…` or decimal).
`--override-nonce`	`ADDR:VALUE`	Set the account nonce.
`--override-code`	`ADDR:HEX`	Replace the account's bytecode.
`--override-state`	`ADDR:SLOT:VALUE`	Replace a storage slot, dropping every other slot for that account.
`--override-state-diff`	`ADDR:SLOT:VALUE`	Overlay a single storage slot, leaving the rest unchanged.
`--override-move-precompile`	`ADDR:TARGET`	Move the precompile at `ADDR` to `TARGET`.

--override-state and --override-state-diff are mutually exclusive for the same address — supplying both for one account is rejected by the node.

Every flag in the table above can be passed multiple times in a single invocation, and different flag types can be mixed freely. All entries are merged into one State Override Set sent as the 3rd eth_call parameter:

Multiple addresses: repeat the same flag with different ADDR values (--override-balance 0xAAA…:0x1 --override-balance 0xBBB…:0x2).
Multiple fields on one address: stack different flags sharing an ADDR (--override-balance 0xAAA…:0x1 --override-nonce 0xAAA…:0x7 --override-code 0xAAA…:0x…).
Multiple storage slots on one address: repeat --override-state-diff (or --override-state) with the same ADDR and different SLOT:VALUE pairs. Don't mix --override-state with --override-state-diff for the same address — the node rejects that combination.

Examples:

# Pin the USDC balance of an address to 0xdeadbeef by overriding the contract's bytecode
rex balance --token 0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48 \
            0x37305b1cd40574e4c5ce33f8e8306be057fd7341 \
            --override-code 0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48:0x63deadbeef60005260206000f3

# Or override the storage slot for that account's balance entry directly
# (slot = keccak256(abi.encode(addr, uint256(9))) — slot 9 holds USDC's balances mapping)
rex balance --token 0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48 \
            0x37305b1cd40574e4c5ce33f8e8306be057fd7341 \
            --override-state-diff 0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48:0x9254cb65314db3d2d7ca17f753f1d9c7f1b6fa05111d18d10ed5b9519d1b247c:0x0123456789

# Stack overrides across addresses:
# - override USDC's balance slot for the target account
# - fabricate a balance + nonce on an unrelated address
rex call 0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48 \
         --calldata 0x70a0823100000000000000000000000037305b1cd40574e4c5ce33f8e8306be057fd7341 \
         --rpc-url http://my-node:8545 \
         --override-state-diff 0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48:0x9254cb65314db3d2d7ca17f753f1d9c7f1b6fa05111d18d10ed5b9519d1b247c:0x42 \
         --override-balance 0x0000000000000000000000000000000000000bad:0x100 \
         --override-nonce   0x0000000000000000000000000000000000000bad:0x7

Block overrides

rex call and rex balance --token … also accept a Block Override Set as the 4th eth_call parameter, matching the format documented at https://geth.ethereum.org/docs/interacting-with-geth/rpc/objects#block-overrides (also implemented in ethrex as of lambdaclass/ethrex#6660).

Each flag replaces one field of the block header the call is simulated against; omitted fields keep the real header values. Unlike state override flags, each flag takes a single value — there is only one block context per call. Numeric values accept hex (0x…) or decimal.

Flag	Format	JSON field	Meaning
`--override-block-number`	`NUMBER`	`number`	Block number (`block.number`).
`--override-block-time`	`TIMESTAMP`	`time`	Block timestamp in unix seconds (`block.timestamp`).
`--override-block-gas-limit`	`GAS`	`gasLimit`	Block gas limit.
`--override-block-coinbase`	`ADDR`	`coinbase`	Fee recipient (`block.coinbase`). Alias: `--override-block-fee-recipient`.
`--override-block-prev-randao`	`HASH`	`random`	PREVRANDAO value (`block.prevrandao`). Alias: `--override-block-random`.
`--override-block-base-fee`	`VALUE`	`baseFeePerGas`	Base fee per gas (EIP-1559).
`--override-block-blob-base-fee`	`VALUE`	`blobBaseFeePerGas`	Blob base fee per gas (EIP-4844).
`--override-block-difficulty`	`VALUE`	`difficulty`	Block difficulty; a no-op on post-merge blocks.

Block and state overrides compose freely in one invocation. When only block override flags are passed, an empty state override object (a no-op) is sent as the 3rd parameter to keep the block override set in 4th position; when neither is passed, the 2-parameter eth_call form is used so older nodes keep working.

Note

The JSON field names follow ethrex and reth (coinbase, random, blobBaseFeePerGas). Recent geth releases renamed these three to feeRecipient, prevRandao and blobBaseFee and silently ignore the older spellings, so against a current geth node those three overrides won't take effect.

Examples:

# Simulate a call one year in the future, e.g. to check that a vesting
# contract releases funds after its cliff
rex call 0x00000000000000000000000000000000000ce11a \
         --calldata 0x86d1a69f \
         --override-block-time 1812837600 \
         --override-block-number 25000000

# Query an ERC-20 balance under a synthetic block context
rex balance --token 0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48 \
            0x37305b1cd40574e4c5ce33f8e8306be057fd7341 \
            --override-block-number 0x1312d00

# Combine state and block overrides in one call
rex call 0x00000000000000000000000000000000000ce11a \
         --calldata 0x86d1a69f \
         --override-balance 0x0000000000000000000000000000000000000bad:0x100 \
         --override-block-coinbase 0x000000000000000000000000000000000000cafe

`rex chain-id`

Get the network's chain id.

Usage: rex chain-id [OPTIONS]

Options:
      --hex                Display the chain id as a hex-string.
      --rpc-url <RPC_URL>  [env: RPC_URL=] [default: http://localhost:8545]
  -h, --help               Print help

`rex code`

Returns code at a given address

Usage: rex code [OPTIONS] <ADDRESS>

Arguments:
  <ADDRESS>

Options:
  -B, --block <BLOCK>      defaultBlock parameter: can be integer block number, 'earliest', 'finalized', 'safe', 'latest' or 'pending' [default: latest]
      --rpc-url <RPC_URL>  [env: RPC_URL=] [default: http://localhost:8545]
  -h, --help               Print help

`rex create-address`

Compute contract address given the deployer address and nonce.

Usage: rex create-address [OPTIONS] <DEPLOYER>

Arguments:
  <DEPLOYER>  Deployer address.

Options:
  -n, --nonce <NONCE>      Deployer Nonce. Latest by default.
      --rpc-url <RPC_URL>  [env: RPC_URL=] [default: http://localhost:8545]
  -h, --help               Print help

`rex create2-address`

Usage: rex create2-address [OPTIONS]

Options:
  -d, --deployer <DEPLOYER>
          Deployer address. Default is Mainnet Deterministic Deployer [default: 0x4e59b44847b379578588920cA78FbF26c0B4956C]
  -i, --init-code <INIT_CODE>
          Initcode of the contract to deploy.
      --init-code-hash <INIT_CODE_HASH>
          Hash of the initcode (keccak256).
  -s, --salt <SALT>
          Salt for CREATE2 opcode
      --begins <BEGINS>
          Address must begin with this hex prefix.
      --ends <ENDS>
          Address must end with this hex suffix.
      --contains <CONTAINS>
          Address must contain this hex substring.
      --case-sensitive
          Make the address search case sensitive when using begins, ends, or contains.
      --threads <THREADS>
          Number of threads to use for brute-forcing. Defaults to the number of logical CPUs. [default: 8]
  -h, --help
          Print help

`rex decode-calldata`

Decodes calldata

Usage: rex decode-calldata <SIGNATURE> <DATA>

Arguments:
  <SIGNATURE>
  <DATA>

Options:
  -h, --help  Print help

`rex deploy`

Deploy a contract

Usage: rex deploy [OPTIONS] <--bytecode <BYTECODE>|--contract-path <CONTRACT_PATH>>

Options:
      --bytecode <BYTECODE>

      --value <VALUE>
          Value to send in wei [default: 0]
      --chain-id <CHAIN_ID>

      --nonce <NONCE>

      --gas-limit <GAS_LIMIT>

      --gas-price <MAX_FEE_PER_GAS>

      --priority-gas-price <MAX_PRIORITY_FEE_PER_GAS>

      --print-address

  -c, --cast
          Send the request asynchronously.
  -s, --silent
          Display only the tx hash.
      --explorer-url
          Display transaction URL in the explorer.
      --private-key <PRIVATE_KEY>
          [env: PRIVATE_KEY=]
      --contract-path <CONTRACT_PATH>
          Path to the Solidity file to compile and deploy
      --remappings <REMAPPINGS>
          Comma-separated remappings (e.g. '@openzeppelin/contracts=https://github.com/OpenZeppelin/openzeppelin-contracts.git,@custom=path/to/custom')
      --keep-deps
          Remove downloaded dependencies after compilation
      --salt <SALT>
          Salt for deploying CREATE2 contracts. If it is provided, the contract will be deployed using CREATE2.
      --rpc-url <RPC_URL>
          [env: RPC_URL=] [default: http://localhost:8545]
  -h, --help
          Print help

`rex encode-calldata`

Encodes calldata

Usage: rex encode-calldata <SIGNATURE> [ARGS]...

Arguments:
  <SIGNATURE>
  [ARGS]...

Options:
  -h, --help  Print help

`rex hash`

Get either the keccak for a given input, the zero hash, the empty string, or a random hash

Usage: rex hash [OPTIONS]

Options:
      --input <INPUT>  The input to hash.
  -z, --zero           The zero hash.
  -r, --random         A random hash.
  -s, --string         Hash of empty string
  -h, --help           Print help

`rex help`

Usage: rex <COMMAND>

Commands:
  address           Get either the account's address from private key, the zero address, or a random address [aliases: addr, a]
  autocomplete      Generate shell completion scripts.
  balance           Get the account's balance info. [aliases: bal, b]
  block-number      Get the current block_number. [aliases: bl]
  call              Make a call to a contract
  chain-id          Get the network's chain id.
  code              Returns code at a given address
  create-address    Compute contract address given the deployer address and nonce.
  create2-address   Compute contract address with CREATE2 opcode.
  deploy            Deploy a contract
  hash              Get either the keccak for a given input, the zero hash, the empty string, or a random hash [aliases: h]
  l2                L2 specific commands.
  nonce             Get the account's nonce. [aliases: n]
  receipt           Get the transaction's receipt. [aliases: r]
  send              Send a transaction
  sign              Sign a message with a private key
  signer            
  transaction       Get the transaction's info. [aliases: tx, t]
  transfer          Transfer funds to another wallet.
  verify-signature  Verify if the signature of a message was made by an account
  encode-calldata   Encodes calldata
  decode-calldata   Decodes calldata
  help              Print this message or the help of the given subcommand(s)

Options:
  -h, --help     Print help
  -V, --version  Print version

`rex l2`

L2 specific commands.

Usage: rex l2 <COMMAND>

Commands:
  balance         Get the account's balance on L2. [aliases: bal, b]
  block-number    Get the current block_number. [aliases: bl]
  call            Make a call to a contract
  chain-id        Get the network's chain id.
  claim-withdraw  Finalize a pending withdrawal.
  deploy          Deploy a contract
  deposit         Deposit funds into some wallet.
  nonce           Get the account's nonce. [aliases: n]
  receipt         Get the transaction's receipt. [aliases: r]
  send            Send a transaction
  transaction     Get the transaction's info. [aliases: tx, t]
  transfer        Transfer funds to another wallet.
  withdraw        Withdraw funds from the wallet.
  message-proof   Get the merkle proof of a L1MessageProof.
  help            Print this message or the help of the given subcommand(s)

Options:
  -h, --help  Print help

`rex nonce`

Get the account's nonce.

Usage: rex nonce [OPTIONS] <ACCOUNT>

Arguments:
  <ACCOUNT>

Options:
      --rpc-url <RPC_URL>  [env: RPC_URL=] [default: http://localhost:8545]
  -h, --help               Print help

`rex receipt`

Get the transaction's receipt.

Usage: rex receipt [OPTIONS] <TX_HASH>

Arguments:
  <TX_HASH>

Options:
      --rpc-url <RPC_URL>  [env: RPC_URL=] [default: http://localhost:8545]
  -h, --help               Print help

`rex send`

Send a transaction

Usage: rex send [OPTIONS] <TO> [ARGS]...

Arguments:
  <TO>
  [ARGS]...

Options:
      --value <VALUE>
          Value to send in wei [default: 0]
      --calldata <CALLDATA>
          [default: ]
      --chain-id <CHAIN_ID>

      --nonce <NONCE>

      --gas-limit <GAS_LIMIT>

      --gas-price <MAX_FEE_PER_GAS>

      --priority-gas-price <MAX_PRIORITY_FEE_PER_GAS>

  -c, --cast
          Send the request asynchronously.
  -s, --silent
          Display only the tx hash.
      --explorer-url
          Display transaction URL in the explorer.
  -k, --private-key <PRIVATE_KEY>
          [env: PRIVATE_KEY=]
      --rpc-url <RPC_URL>
          [env: RPC_URL=] [default: http://localhost:8545]
  -h, --help
          Print help

`rex sign`

Sign a message with a private key

Usage: rex sign --private-key <PRIVATE_KEY> <MSG>

Arguments:
  <MSG>  Message to be signed with the private key.

Options:
      --private-key <PRIVATE_KEY>  The private key to sign the message. [env: PRIVATE_KEY=]
  -h, --help                       Print help

`rex signer`

Usage: rex signer <MESSAGE> <SIGNATURE>

Arguments:
  <MESSAGE>
  <SIGNATURE>

Options:
  -h, --help  Print help

`rex transaction`

Get the transaction's info.

Usage: rex transaction [OPTIONS] <TX_HASH>

Arguments:
  <TX_HASH>

Options:
      --rpc-url <RPC_URL>  [env: RPC_URL=] [default: http://localhost:8545]
  -h, --help               Print help

`rex transfer`

Transfer funds to another wallet.

Usage: rex transfer [OPTIONS] <AMOUNT> <TO>

Arguments:
  <AMOUNT>
  <TO>

Options:
      --token <TOKEN_ADDRESS>
      --nonce <NONCE>
  -c, --cast                       Send the request asynchronously.
  -s, --silent                     Display only the tx hash.
      --explorer-url               Display transaction URL in the explorer.
      --private-key <PRIVATE_KEY>  [env: PRIVATE_KEY=]
      --rpc-url <RPC_URL>          [env: RPC_URL=] [default: http://localhost:8545]
  -h, --help                       Print help

`rex verify-signature`

Verify if the signature of a message was made by an account

Usage: rex verify-signature <MESSAGE> <SIGNATURE> <ADDRESS>

Arguments:
  <MESSAGE>
  <SIGNATURE>
  <ADDRESS>

Options:
  -h, --help  Print help

Examples

A curated list of examples as GIFs.

TODO