Example using multiple tfvars files

tfvars_example.sh

thq-d-bburt01 福 ~/code/lookout/terraform/tf_example ➤ 608cc3b|master✓
4299 ± : terraform plan -var-file terraform_main.tfvars                                                                                    
Refreshing Terraform state prior to plan...

Error refreshing state: 1:3: unknown variable accessed: var.aws_access_key in:

${var.aws_access_key}

thq-d-bburt01 福 ~/code/lookout/terraform/tf_example ➤ 608cc3b|master✓
4300 ± : terraform plan -var-file terraform_main.tfvars -var-file terraform_aws.tfvars                                                     
Refreshing Terraform state prior to plan...


The Terraform execution plan has been generated and is shown below.
Resources are shown in alphabetical order for quick scanning. Green resources
will be created (or destroyed and then created if an existing resource
exists), yellow resources are being changed in-place, and red resources
will be destroyed.

Note: You didn't specify an "-out" parameter to save this plan, so when
"apply" is called, Terraform can't guarantee this is what will execute.

+ module.sg_memcached
    1 resource(s)
+ module.sg_web
    1 resource(s)
+ module.example_memcached_autoscaling_group
    2 resource(s)
+ module.example_web_autoscaling_group
    2 resource(s)