This is a simple Go program that finds the first firstup.env file starting from the current directory walking upward, stopping before the root folder (meaning: any /firstup.env file will not be read).

It will write the env vars as export statements. It will also store the list of keys set in a separate environment variable and unset those next time firstupdotenv is run.

The output may then look like this:

unset FOO
unset BAR
export FIRSTUPDOTENV_CURRENT_SET_ENV=FOO,BAR
export FOO=value1
export BAR=value2

The .env format is a file on the form key=value. It ignores empty lines and lines starting with # and lines without an equals sign. If the same key is defined more than once, the last will win.

To install:

go install github.com/bep/firstupdotenv@latest

This tool is meant to be used in combination with some shell extension that triggers when you cd into a directory. If you use the Z shell, putting this in your .zshrc will work:

autoload -U add-zsh-hook

firstupdotenv_after_cd() {
	source <(firstupdotenv)
}

add-zsh-hook chpwd firstupdotenv_after_cd