Updated steps to include MacOS and Linux support

Added MacOS and Linux steps for "Retrieve managed identity of the Arc Data Controller Extension" and "Assign role to the managed identity"

Author: clayton006

articles/azure-arc/data/upload-metrics.md

@@ -33,19 +33,35 @@ The Arc data services extension managed identity is used for uploading metrics.
 
 ### (1) Retrieve managed identity of the Arc data controller extension
 
+# [PowerShell](#tab/powershell)
 ```powershell
 $Env:MSI_OBJECT_ID = (az k8s-extension show --resource-group <resource group>  --cluster-name <connectedclustername> --cluster-type connectedClusters --name <name of extension> | convertFrom-json).identity.principalId
 #Example
 $Env:MSI_OBJECT_ID = (az k8s-extension show --resource-group myresourcegroup  --cluster-name myconnectedcluster --cluster-type connectedClusters --name ads-extension | convertFrom-json).identity.principalId
 ```
 
+# [macOS & Linux](#tab/linux)
+```console
+export MSI_OBJECT_ID=`az k8s-extension show --resource-group <resource group>  --cluster-name <connectedclustername>  --cluster-type connectedClusters --name <name of extension> | jq '.identity.principalId' | tr -d \"`
+#Example
+export MSI_OBJECT_ID=`az k8s-extension show --resource-group myresourcegroup  --cluster-name myconnectedcluster --cluster-type connectedClusters --name ads-extension | jq '.identity.principalId' | tr -d \"`
+```
+
+---
+
 ### (2) Assign role to the managed identity
 
 Run the below command to assign the **Monitoring Metrics Publisher** role:
+# [PowerShell](#tab/powershell)
 ```powershell
 az role assignment create --assignee $Env:MSI_OBJECT_ID --role 'Monitoring Metrics Publisher' --scope "/subscriptions/$SUBSCRIPTION_ID/resourceGroups/$RESOURCE_GROUP_NAME"
+```
 
+# [macOS & Linux](#tab/linux)
+```console
+az role assignment create --assignee ${MSI_OBJECT_ID} --role 'Monitoring Metrics Publisher' --scope "/subscriptions/${subscription}/resourceGroups/${resourceGroup}"
 ```
+---
 
 ### Automatic upload of metrics can be enabled as follows:
 ```