tool to ensure that the environment variables match expectations

 The envassert script, accompanied by the Env::Assert module, checks that
 your runtime environment, as defined with environment variables, matches with
 what you want.
 .
 You can define your required environment in a file.
 Default file is .envassert but you can use any file.
 .
 It is advantageous to use envassert for examnple when running a container. If
 you check your environment for missing or wrongly defined environment
 variables at the beginning of the container run, your container will fail
 sooner instead of in a later point in execution when the variables are
 needed.