Eval an env file and execute a command. This script is implemented by bash, so it can expand a shell-format expression of the form $VARIABLE, ${VARIABLE} or $(command-list).

Fetch the script, chmod +x dotenv and put it somewhere in your PATH.

For example:

sudo curl -o /usr/local/bin/dotenv -L https://raw.githubusercontent.com/ttakezawa/dotenv/master/dotenv && sudo chmod +x /usr/local/bin/dotenv

Create your env file.

Example env file:

VAR1=Hello
VAR2=${USER}
VAR3=$(ls | wc -l)

Use dotenv.

dotenv .env sh -c 'echo "$VAR1 $VAR2. Current directory has $VAR3 entries."'