This assumes you have already configured the aws command line tool. If not, check out my article on Getting Started with the AWS CLI.

The aws ec2 describe-route-tables command can be used to list your Route Tables.

aws ec2 describe-route-tables

And here is an example of how to limit the output using the --query option to list the route table in a specific Virtual Private Cloud (VPC).

aws ec2 describe-route-tables --query 'RouteTables[?VpcId==`vpc-014d2fcfa335d3c01`]'

Something like this should be returned.

[
    {
        "Associations": [
            {
                "AssociationState": {
                    "State": "associated"
                },
                "RouteTableAssociationId": "rtbassoc-03d88b8f543d22956",
                "Main": true,
                "RouteTableId": "rtb-0587dc78ea0f59472"
            }
        ],
        "RouteTableId": "rtb-0587dc78ea0f59472",
        "VpcId": "vpc-014d2fcfa335d3c01",
        "PropagatingVgws": [],
        "Tags": [
            {
                "Value": "ManagedByAmazonFSx",
                "Key": "AmazonFSx"
            }
        ],
        "Routes": [
            {
                "GatewayId": "local",
                "DestinationCidrBlock": "172.31.0.0/16",
                "State": "active",
                "Origin": "CreateRouteTable"
            },
            {
                "GatewayId": "igw-020c1f7ec148352b3",
                "DestinationCidrBlock": "0.0.0.0/0",
                "State": "active",
                "Origin": "CreateRoute"
            }
        ],
        "OwnerId": "123456789012"
    }
]