l2geth: start script ws (#806)

* l2geth: add wsport parsing to start script

* chore: add changeset

.changeset/sour-onions-burn.md

+---
+'@eth-optimism/l2geth': patch
+---
+
+Update `scripts/start.sh` to parse the websocket port and pass to geth at runtime

l2geth/scripts/start.sh

@@ -17,6 +17,7 @@ ROLLUP_POLL_INTERVAL=15s
 ROLLUP_TIMESTAMP_REFRESH=3m
 CACHE=1024
 RPC_PORT=8545
+WS_PORT=8546
 VERBOSITY=3
 
 USAGE="
@@ -84,6 +85,15 @@ while (( "$#" )); do
                 exit 1
             fi
             ;;
+        --wsport)
+            if [ -n "$2" ] && [ ${2:0:1} != "-" ]; then
+                WS_PORT="$2"
+                shift 2
+            else
+                echo "Error: Argument for $1 is missing" >&2
+                exit 1
+            fi
+            ;;
         --eth1.ctcdeploymentheight)
             if [ -n "$2" ] && [ ${2:0:1} != "-" ]; then
                 ETH1_CTC_DEPLOYMENT_HEIGHT="$2"
@@ -222,7 +232,7 @@ cmd="$cmd --rpccorsdomain '*'"
 cmd="$cmd --rpcvhosts '*'"
 cmd="$cmd --ws"
 cmd="$cmd --wsaddr 0.0.0.0"
-cmd="$cmd --wsport 8546"
+cmd="$cmd --wsport $WS_PORT"
 cmd="$cmd --wsorigins '*'"
 cmd="$cmd --rpcapi 'eth,net,rollup,web3,debug'"
 cmd="$cmd --gasprice 0"