add dump command doc

Author: Pana

docs/commands/readme.md

@@ -6,34 +6,26 @@ Currently Available Subcommands：
 
 - `account`：Account Management
 - `rpc`：RPC-based subcommands, used for querying blockchain information and sending transactions
+- `dump`: Dump eSpace account state at a given block number
 - `help`：Print help message
 
 ```sh
-./conflux -h
-conflux conflux-rust/v2.4.0-82500ad-20250418/x86_64-linux-gnu/rustc1.77.2
-The Conflux Team
-Conflux client.
+Conflux client
 
-USAGE:
-    conflux [FLAGS] [OPTIONS] [SUBCOMMAND]
+Usage: conflux [OPTIONS] [COMMAND]
 
-FLAGS:
-        --archive       
-        --full          
-    -h, --help          Prints help information
-        --light         
-        --tg_archive    
-    -V, --version       Prints version information
-
-OPTIONS:
-    -c, --config <FILE> Sets a custom config file.
-    ...
-    
+Commands:
+  account  Manage accounts
+  dump     Dump eSpace account state at a given block number
+  rpc      RPC based subcommands to query blockchain information and send transactions
+  help     Print this message or the help of the given subcommand(s)
 
-SUBCOMMANDS:
-    account    Manage accounts
-    help       Prints this message or the help of the given subcommand(s)
-    rpc        RPC based subcommands to query blockchain information and send transactions
+Options:
+      --mode <MODE>
+          Use the preset testing configurations. dev or test
+  -p, --port <PORT>
+          Specify the port for P2P connections
+  ...
 ```
 
 Each command-line tool comes with its own help information. Users can view the help message by using the -h or --help flag.
@@ -57,4 +49,46 @@ SUBCOMMANDS:
     import    Import accounts from JSON UTC keystore files to the specified --chain (default conflux)
     list      List existing accounts of the given --chain (default conflux).
     new       Create a new account (and its associated key) for the given --chain (default conflux).
-```
+```
+
+## dump subcommand
+
+This command can be used to export all account states at a certain block height in eSpace to JSON files, facilitating development and debugging. The exported data structure example is as follows
+
+```sh
+$ ./conflux --config devnode.toml dump --block 1000 # export state at height 1000
+{
+  "root": "0xdd606752e465cb6a1e2f0df718057536ab00cd66d9c6fa46085309145823d3c0",
+  "accounts": {
+    "0x004e322e7ea7e63547d25639d8e8ed282318eec9": {
+      "balance": "0x152cfd9872b245dcbcae",
+      "nonce": 210,
+      "root": "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
+      "codeHash": "0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470",
+      "address": "0x004e322e7ea7e63547d25639d8e8ed282318eec9",
+      "key": "0x0c1bad9586421be5b0d8eda4446cac4ce7692d67301d07146a87455e7bc9d30e"
+    },
+    "0x0c80d6926edc73977dce4c97ff8966abf04fe80e": {
+      "balance": "0x0",
+      "nonce": 2,
+      "root": "0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
+      "codeHash": "0xe79d1e04e3004c8d97ad51f5f08cfd1a79e6cdcce2a3a6d59676a9858bccd173",
+      "code": "0xf90338b903206080604052600436106100385760003.....",
+      "storage": {
+        "0x0000000000000000000000000000000000000000000000000000000000000000": "0xc",
+        "0x0000000000000000000000000000000000000000000000000000000000000001": "0x27e26b9234ec81a0247a6083edf8b329fb1ccde9"
+      },
+      "address": "0x0c80d6926edc73977dce4c97ff8966abf04fe80e",
+      "key": "0x691460d9548cee180ba8cd9f0960fee74fed16501d80cdb3182aa0f41b160e54"
+    }
+  }
+}
+```
+
+Note: 
+
+1. Conflux contract data storage differs significantly from Ethereum, as it is not stored in separate MPT form, therefore the storage root cannot be obtained. The exported data's `account.root` is fixed as `0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421`
+2. The exported root information is the full state root of Conflux dual-space (Core Space, eSpace), only for maintaining data format consistency, not the state root of all eSpace accounts.
+3. When exporting mainnet state data, due to the large number of accounts, high machine configuration is required, and the runtime will be quite long; if you want to export the state at a certain height in history, it needs to be performed on a fullstate node data.
+4. When performing state export, please stop the node program first, then execute the export operation in the node directory.
+5. Please use the binary corresponding to the network and execute the export operation in the corresponding network data directory; do not use testnet or master code compiled binary to execute export operations on mainnet data.