feat: added script to fetch tx hasg from block height & tx index

scripts/get_tx_from_block.sh

@@ -0,0 +1,42 @@
+#!/bin/bash
+#
+# This script fetches a transaction hash using block height and transaction index
+# Usage: ./get_tx_from_block.sh <block_height> <tx_index>
+
+if [ "$#" -ne 2 ]; then
+    echo "Usage: $0 <block_height> <tx_index>"
+    echo "Example: $0 869322 1"
+    exit 1
+fi
+
+BLOCK_HEIGHT=$1
+TX_INDEX=$2
+
+RPC_API="https://bitcoin-mainnet.public.blastapi.io"
+
+# First, get the block hash for the given height
+BLOCK_HASH_RES=$(curl -s -X POST -H "Content-Type: application/json" \
+    -d "{\"jsonrpc\":\"1.0\",\"id\":0,\"method\":\"getblockhash\",\"params\":[$BLOCK_HEIGHT]}" \
+    $RPC_API)
+
+BLOCK_HASH=$(echo $BLOCK_HASH_RES | jq -r '.result')
+
+if [ -z "$BLOCK_HASH" ] || [ "$BLOCK_HASH" = "null" ]; then
+    echo "Error: Could not fetch block hash for height $BLOCK_HEIGHT"
+    exit 1
+fi
+
+# Then, get the block data which includes all transaction hashes
+BLOCK_DATA_RES=$(curl -s -X POST -H "Content-Type: application/json" \
+    -d "{\"jsonrpc\":\"1.0\",\"id\":0,\"method\":\"getblock\",\"params\":[\"$BLOCK_HASH\"]}" \
+    $RPC_API)
+
+# Extract the transaction hash at the specified index
+TX_HASH=$(echo $BLOCK_DATA_RES | jq -r ".result.tx[$TX_INDEX]")
+
+if [ -z "$TX_HASH" ] || [ "$TX_HASH" = "null" ]; then
+    echo "Error: Could not find transaction at index $TX_INDEX in block $BLOCK_HEIGHT"
+    exit 1
+fi
+
+echo $TX_HASH