module "files" {
  source  = "matti/resource/shell"
  command = "ls -l"
}

output "my_files" {
  value = module.files.stdout
}

...
Apply complete! Resources: 3 added, 0 changed, 0 destroyed.

Outputs:

my_files = total 16
-rw-r--r--  1 mpa  staff   112 Feb  9 09:06 main.tf
-rw-r--r--  1 mpa  staff  1007 Feb  9 09:07 terraform.tfstate

module "first" {
  source = "matti/resource/shell"

  command = ">/tmp/first echo I was here first"
}

module "greeting" {
  source = "matti/resource/shell"

  # workaround for missing depends_on in modules
  depends = [
    module.first.id
  ]

  environment = {
    GREETING = "hello"
  }

  command              = "echo $GREETING world from $(pwd) where /tmp/first has content: $(cat /tmp/first)"
  command_when_destroy = "echo $GREETING and good bye from $(pwd)"

  # runs on every apply
  trigger = timestamp()

  working_dir = "/tmp"

  # mark outputs (stdout & stderr) as sensitive
  # sensitive_outputs = true
}

output "greeting" {
  value = module.greeting.stdout
}

Apply complete! Resources: 6 added, 0 changed, 0 destroyed.

Outputs:

greeting = hello world from /private/tmp where /tmp/first has content: I was here first