fix python3 -m evm_tools t8n -v version flag output

src/ethereum_spec_tools/evm_tools/t8n/__init__.py

@@ -5,10 +5,11 @@
 import argparse
 import json
 import os
+import subprocess
 import sys
 from typing import Any
 
-from ethereum import rlp, trace
+from ethereum import rlp, trace, __version__
 from ethereum.base_types import U64, U256, Uint
 from ethereum.crypto.hash import keccak256
 from ethereum_spec_tools.forks import Hardfork
@@ -25,11 +26,42 @@
 from .t8n_types import Alloc, Result, Txs
 
 
+def get_git_commit_hash() -> str:
+    """
+    Run the 'git rev-parse HEAD' command to get the commit hash
+    """
+    try:
+        result = subprocess.run(
+            ["git", "rev-parse", "HEAD"],
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+            text=True,
+            check=True,
+        )
+
+        # Extract and return the commit hash
+        commit_hash = result.stdout.strip()
+        return commit_hash
+    # Handle errors (e.g., Git not found, not in a Git repository)
+    except FileNotFoundError as e:
+        return str(e)
+    except subprocess.CalledProcessError as e:
+        return "Error: " + str(e)
+
+
 def t8n_arguments(subparsers: argparse._SubParsersAction) -> None:
     """
     Adds the arguments for the t8n tool subparser.
     """
     t8n_parser = subparsers.add_parser("t8n", help="This is the t8n tool.")
+    commit_hash = get_git_commit_hash()
+    t8n_parser.add_argument(
+        "-v",
+        "--version",
+        action="version",
+        help="show t8n script version and exit",
+        version=f"PYSPECS %(prog)s {__version__} (Git commit: {commit_hash})",
+    )
 
     t8n_parser.add_argument(
         "--input.alloc", dest="input_alloc", type=str, default="alloc.json"