The OpenFaaS CLI, faas-cli, is a command-line tool to help manage, prepare, and invoke functions. On Linux, the OpenFaaS CLI can be installed using the following command:

$ curl -sSL https://cli.openfaas.com | sudo sh

On macOS, it can be installed via brew with the following command:

$ brew install faas-cli

Alternatively, on Windows, faas-cli.exe can be downloaded directly from the OpenFaaS GitHub repository and run manually.

However, we assume that every example is running on Linux. In the following example, the hello function will be created using OpenFaaS's template for the Go language, which can be found at openfaas/fass-cli in GitHub in the template/go directory.

Locally, all templates will be stored in the template/ directory of the working directory. If the template directory does not exist, all templates will be fetched from GitHub's, openfaas/faas-cli. As of OpenFaaS 0.6, there are 10 available templates for five different programming languages there.