Azure CLI how to check if a resource exists

Question

I'm starting to write a bash script to provision a VM in a new or existing resource group so that we can enforce naming convention and configuration.

In a bash script how can I check that a resource already exists so I don't try to create it again?

# 1.    If a new resource group is desired, create it now.  Microsoft Docs
az group create --name $RESOURCEGROUPNAME --location $LOCATION

# 2.    Create a virtual network and subnet if one has not already been created.  Microsoft Docs
#   Consider a separate VNet for each resource group. 
#   az network vnet list -output table
az network vnet create \
  --resource-group $RESOURCEGROUPNAME \
  --name $RESOURCEGROUPNAME-vnet \
  --address-prefix 10.0.x.0/24 \
  --subnet-name default \
  --subnet-prefix 10.0.x.0/24

# x is the next available 3rd octet value

# 3.    Create a public IP Address.  Microsoft Docs
az network public-ip create \
  --resource-group $RESOURCEGROUPNAME \
  --name $VMNAME-ip \
  --dns-name $DNSNAME

# 4.    Create a network security group.  Microsoft Docs
az network nsg create \
  --resource-group $RESOURCEGROUPNAME \
  --name $VMNAME-nsg 

# 5.    Create a rule to allow SSH to the machine.  Microsoft Docs
az network nsg rule create \
  --resource-group $RESOURCEGROUPNAME \
  --nsg-name $VMNAME-nsg \
  --name allow-ssh \
  --protocol tcp \
  --priority 1000 \
  --destination-port-range 22 \
  --access allow

# 6.    Create a virtual NIC.   Microsoft Docs
az network nic create \
  --resource-group $RESOURCEGROUPNAME \
  --name $VMNAME-nic \
  --vnet-name $RESOURCEGROUPNAME-vnet \
  --subnet default \
  --public-ip-address $VMNAME-ip \
  --network-security-group $VMNAME-nsg

# 7.    Create an availability set, if redundancy is required.  Microsoft Docs
az vm availability-set create \
  --resource-group $RESOURCEGROUPNAME \
  --name $AVSETNAME-as

# 8.    Create the VM. Microsoft Docs
az vm create \
  --resource-group $RESOURCEGROUPNAME \
  --location $LOCATION \
  --name $VMNAME \
  --image UbuntuLTS \
  --size $VMSIZE \
  --availability-set $AVSETNAME-as \
  --nics $VMNAME-nic \
  --admin-username $ADMINUSERNAME \
  --authentication-type ssh
  --ssh-key-value @$SSHPUBLICKEYFILE \
  --os-disk-name $VMNAME-osdisk

Answer 1

This should work in bash script:

if [ $(az group exists --name $RESOURCEGROUPNAME) = false ]; then
    az group create --name $RESOURCEGROUPNAME --location $LOCATION
fi