direnv

Grant direnv permission to load the .envrc present in the current directory

$ direnv allow [.]

$ direnv deny [.]

$ direnv edit [.]

$ direnv reload

$ direnv status

direnv COMMAND [options] [args...]
Load/unload env vars via .envrc per directory.

allow
    Grant permission to load current .envrc

deny
    Revoke permission and unload .envrc

edit
    Open .envrc in $EDITOR safely

reload
    Reload environment from current .envrc

status
    Show if direnv is active and details

watch [file]...
    Watch files/dirs for auto-reload

exec dir cmd [args]...
    Load env from dir, run cmd

--help
    Show help for command

--version
    Print direnv version

--verbose
    Enable debug output

Direnv is a battery-included shell extension that manages project-specific environment variables. It automatically loads and unloads environment variables when you cd into a directory containing a .envrc file.

Each .envrc contains shell commands (e.g., export PATH=./bin:$PATH, use python) that modify the environment safely. Direnv executes trusted .envrc files on directory entry and restores the previous state on exit, preventing global pollution.

Key features include a permission system (direnv allow/deny) to review code before execution, support for watchers to reload on file changes, and standards like layout functions for common tools (e.g., Ruby, Node, Python virtualenvs).

It's lightweight, secure (sandboxed eval), and hooks into shells like bash, zsh, fish. Ideal for developers switching projects without manual source commands. Widely used in open-source and enterprise for reproducible environments.

Requires shell hook setup (e.g., eval "$(direnv hook bash)" in .bashrc). Untrusted .envrc prompts for review to avoid malicious code. May slow cd in deeply nested dirs with many watchers. Not active without hook.

Add to shell rc:
eval "$(direnv hook $SHELL)" for bash/zsh/fish.

export DATABASE_URL=postgresql://localhost/myapp
PATH_add ./bin
use flake
Review with direnv allow.

Created by Denis Knauf in 2012 as a successor to autoenv. Gained popularity via GitHub (direnv/direnv). Major v2.0 in 2019 added layouts and better security. Actively maintained, used by 100k+ devs for modern workflows.

env(1), bash(1), zsh(1)