tfenv is a Terraform version manager that allows you to easily switch between different versions of Terraform on your machine. It is a command-line tool that can be used to manage and install different versions of Terraform.

In Node.js, you can read environment variables using the process.env object. This object provides access to all environment variables that are set when the Node.js process was started.

In Node.js, you can write data to files using the built-in fs module. fs.writeFile() function is used to writing a file asynchronously. fs.writeFileSync() function is used to writing a file synchronously.

​An equivalent of the 'which' command on the Windows command line is 'where' and it serves the same purpose as 'which' on Unix-like systems.

gRPC is a high-performance open-source framework for remote procedure calls (RPCs). It uses Protocol Buffers, a language-agnostic data serialization format, and provides support for various programming languages and platforms, including Node.js.

Bower and npm are both package managers for front-end web development, but there are some differences between them. Bower requires both Node.js and Git to be installed, while npm only requires Node.js. This means that npm is easier to install and set up.

In JavaScript, null and undefined are both special values that represent the absence of a value, but they are different in their meaning and behavior.