printenv

The printenv command shows us the variables, and their values, that are stored in our working shell environment.

$ tldr printenv
$ printenv | grep ^USER
$ printenv | grep ^SHELL

Get the value of a variable

$ echo "$SHELL"
$ echo "$EDITOR"

API keys

When working with a Web API, it's good practice to keep your API key separate from your code. By storing these values in your environment, you can define this API key ouside of your code, and still easily access its value.

First, store the key-value pair in a file.

# ~/.env
export TMDB_API_KEY=tmdb-api-key-value

Then, source the file to load the key-value pair into the working shell environment.

$ source ~/.env # or
$ . ~/.env
$ curl https://api.themoviedb.org/3/movie/615643?api_key=$TMDB_API_KEY

Pretty-print the output with jq

$ curl https://api.themoviedb.org/3/movie/615643?api_key=$TMDB_API_KEY | jq

Load Environment Variables

Load the variables stored in ~/.env when starting the terminal, before reaching the bash prompt.

# ~/.bashrc

# load user-set environment variables
ENV_VARIABLES="$HOME/.env"
if [[ -f "$ENV_VARIABLES" ]]; then
  source "$ENV_VARIABLES"
fi