DIRENV-STDLIB 1 “2019” direnv “User Manuals”


direnv-stdlib - functions for the .envrc


direnv stdlib


Outputs a bash script called the stdlib. The following commands are included in that script and loaded in the context of an .envrc. In addition, it also loads the file in ~/.config/direnv/direnvrc if it exists.


has <command>

Returns 0 if the command is available. Returns 1 otherwise. It can be a binary in the PATH or a shell function.


if has curl; then
  echo "Yes we do"

expand_path <rel_path> [<relative_to>]

Outputs the absolute path of rel_path relative to relative_to or the current directory.


cd /usr/local/games
expand_path ../foo
# output: /usr/local/foo

dotenv [<dotenv_path>]

Loads a “.env” file into the current environment.

dotenv_if_exists [<dotenv_path>]

Loads a “.env” file into the current environment, but only if it exists.

user_rel_path <abs_path>

Transforms an absolute path abs_path into a user-relative path if possible.


echo $HOME
# output: /home/user
user_rel_path /home/user/my/project
# output: ~/my/project
user_rel_path /usr/local/lib
# output: /usr/local/lib

find_up <filename>

Outputs the path of filename when searched from the current directory up to /. Returns 1 if the file has not been found.


cd /usr/local/my
mkdir -p project/foo
touch bar
cd project/foo
find_up bar
# output: /usr/local/my/bar

source_env <file_or_dir_path>

Loads another .envrc either by specifying its path or filename.

NOTE: the other .envrc is not checked by the security framework.

source_env_if_exists <filename>

Loads another “.envrc”, but only if it exists.

NOTE: contrary to source_env, this only works when passing a path to a file, not a directory.


source_env_if_exists .envrc.private

env_vars_required <varname> [<varname> ...]

Logs error for every variable not present in the environment or having an empty value.
Typically this is used in combination with source_env and source_env_if_exists.


# expect .envrc.private to provide tokens
source_env .envrc.private
# check presence of tokens
env_vars_required GITHUB_TOKEN OTHER_TOKEN

source_up [<filename>]

Loads another .envrc if found with the find_up command. Returns 1 if no file is found.

NOTE: the other .envrc is not checked by the security framework.

source_up_if_exists [<filename>]

Loads another .envrc if found with the find_up command. If one is not found, nothing happens.

NOTE: the other .envrc is not checked by the security framework.

source_url <url> <integrity-hash>

Loads another script from the given url. Before loading it will check the integrity using the provided integrity-hash.

To find the value of the integrity-hash, call direnv fetchurl <url> and extract the hash from the outputted message.

See also direnv-fetchurl(1) for more details.

fetchurl <url> [<integrity-hash>]

Fetches the given url onto disk and outputs its path location on stdout.

If the integrity-hash argument is provided, it will also check the integrity of the script.

See also direnv-fetchurl(1) for more details.

direnv_apply_dump <file>

Loads the output of direnv dump that was stored in a file.

direnv_load [<command-generating-dump-output>]

Applies the environment generated by running argv as a command. This is useful for adopting the environment of a child process - cause that process to run “direnv dump” and then wrap the results with direnv_load.


direnv_load opam exec direnv dump

PATH_add <path>

Prepends the expanded path to the PATH environment variable. It prevents a common mistake where PATH is replaced by only the new path.


# output: /home/user/my/project
PATH_add bin
echo $PATH
# output: /home/user/my/project/bin:/usr/bin:/bin

MANPATH_add <path>

Prepends the expanded path to the MANPATH environment variable. It takes care of man-specific heuritic.

path_add <varname> <path>

Works like PATH_add except that it’s for an arbitrary varname.

PATH_rm <pattern> [<pattern> ...]

Removes directories that match any of the given shell patterns from the PATH environment variable. Order of the remaining directories is preserved in the resulting PATH.

Bash pattern syntax: https://www.gnu.org/software/bash/manual/html_node/Pattern-Matching.html


echo $PATH
# output: /dontremove/me:/remove/me:/usr/local/bin/:...
PATH_rm '/remove/*'
echo $PATH
# output: /dontremove/me:/usr/local/bin/:...

load_prefix <prefix_path>

Expands some common path variables for the given prefix_path prefix. This is useful if you installed something in the prefix_path using ./configure --prefix=$prefix_path && make install and want to use it in the project.

Variables set:



./configure --prefix=$HOME/rubies/ruby-1.9.3
make && make install
# Then in the .envrc
load_prefix ~/rubies/ruby-1.9.3

semver_search <directory> <folder_prefix> <partial_version>

Search a directory for the highest version number in SemVer format (X.Y.Z).


$ tree .
|-- dir
    |-- program-1.4.0
    |-- program-1.4.1
    |-- program-1.5.0
$ semver_search "dir" "program-" "1.4.0"
$ semver_search "dir" "program-" "1.4"
$ semver_search "dir" "program-" "1"

layout <type>

A semantic dispatch used to describe common project layouts.

layout go

Adds “$(direnv_layout_dir)/go” to the GOPATH environment variable. And also adds “$PWD/bin” to the PATH environment variable.

layout julia

Sets the JULIA_PROJECT environment variable to the current directory.

layout node

Adds “$PWD/node_modules/.bin” to the PATH environment variable.

layout php

Adds “$PWD/vendor/bin” to the PATH environment variable.

layout perl

Setup environment variables required by perl’s local::lib See http://search.cpan.org/dist/local-lib/lib/local/lib.pm for more details.

layout pipenv

Similar to layout python, but uses Pipenv to build a virtualenv from the Pipfile located in the same directory. The path can be overridden by the PIPENV_PIPFILE environment variable.

Note that unlike invoking Pipenv manually, this does not load environment variables from a .env file automatically. You may want to add dotenv .env to copy that behavior.

layout pyenv [<version> ...]

Similar to layout python, but uses pyenv to build a virtualenv with the specified Python interpreter version.

Multiple versions may be specified separated by spaces; please refer to the pyenv documentation for more information.

layout python [<python_exe>]

Creates and loads a virtualenv environment under $PWD/.direnv/python-$python_version. This forces the installation of any egg into the project’s sub-folder.

It’s possible to specify the python executable if you want to use different versions of python (eg: layout python python3).

Note that previously virtualenv was located under $PWD/.direnv/virtualenv and will be re-used by direnv if it exists.

layout python3

A shortcut for layout python python3

layout ruby

Sets the GEM_HOME environment variable to $PWD/.direnv/ruby/RUBY_VERSION. This forces the installation of any gems into the project’s sub-folder. If you’re using bundler it will create wrapper programs that can be invoked directly instead of using the bundle exec prefix.

use <program_name> [<version>]

A semantic command dispatch intended for loading external dependencies into the environment.


use_ruby() {
  echo "Ruby $1"
use ruby 1.9.3
# output: Ruby 1.9.3

use julia <version>

Loads the specified Julia version. You must specify a path to the directory with installed Julia versions using $JULIA_VERSIONS. You can optionally override the prefix for folders inside $JULIA_VERSIONS (default julia-) using $JULIA_VERSION_PREFIX. If no exact match for <version> is found a search will be performed and the latest version will be loaded.

Examples (.envrc):

use julia 1.5.1   # loads $JULIA_VERSIONS/julia-1.5.1
use julia 1.5     # loads $JULIA_VERSIONS/julia-1.5.1
use julia master  # loads $JULIA_VERSIONS/julia-master

use rbenv

Loads rbenv which add the ruby wrappers available on the PATH.

use nix [...]

Load environment variables from nix-shell.

If you have a default.nix or shell.nix these will be used by default, but you can also specify packages directly (e.g use nix -p ocaml).

See http://nixos.org/nix/manual/#sec-nix-shell

use flake [<installable>]

Load the build environment of a derivation similar to nix develop.

By default it will load the current folder flake.nix devShell attribute. Or pass an “installable” like “nixpkgs#hello” to load all the build dependencies of the hello package from the latest nixpkgs.

Note that the flakes feature is hidden behind an experimental flag, which you will have to enable on your own. Flakes is not considered stable yet.

use guix [...]

Load environment variables from guix shell.

Any arguments given will be passed to guix shell. For example, use guix hello would setup an environment including the hello package. To create an environment with the hello dependencies, the --development flag is used use guix --development hello. Other options include --file which allows loading an environment from a file.

See https://guix.gnu.org/en/manual/en/guix.html#Invoking-guix-shell

rvm [...]

Should work just like in the shell if you have rvm installed.

use node [<version>]:

Loads the specified NodeJS version into the environment.

If a partial NodeJS version is passed (i.e. 4.2), a fuzzy match is performed and the highest matching version installed is selected.

If no version is passed, it will look at the ‘.nvmrc’ or ‘.node-version’ files in the current directory if they exist.

Environment Variables:

use vim [<vimrc_file>]

Prepends the specified vim script (or .vimrc.local by default) to the DIRENV_EXTRA_VIMRC environment variable.

This variable is understood by the direnv/direnv.vim extension. When found, it will source it after opening files in the directory.

watch_file <path> [<path> ...]

Adds each file to direnv’s watch-list. If the file changes direnv will reload the environment on the next prompt.

Example (.envrc):

watch_file Gemfile

direnv_version <version_at_least>

Checks that the direnv version is at least old as version_at_least. This can be useful when sharing an .envrc and to make sure that the users are up to date.

strict_env [<command> ...]

Turns on shell execution strictness. This will force the .envrc evaluation context to exit immediately if:

If followed by a command-line, the strictness applies for the duration of the command.

Example (Whole Script):

has curl

Example (Command):

strict_env has curl

unstrict_env [<command> ...]

Turns off shell execution strictness. If followed by a command-line, the strictness applies for the duration of the command.

Example (Whole Script):

has curl

Example (Command):

unstrict_env has curl

on_git_branch [<branch_name>]

Returns 0 if within a git repository with given branch_name. If no branch name is provided, then returns 0 when within any branch. Requires the git command to be installed. Returns 1 otherwise.

When a branch is specified, then .git/HEAD is watched so that entering/exiting a branch triggers a reload.

Example (.envrc):

if on_git_branch child_changes; then
  export MERGE_BASE_BRANCH=parent_changes

if on_git_branch; then
  echo "Thanks for contributing to a GitHub project!"

MIT licence - Copyright (C) 2019 @zimbatm and contributors


direnv(1), direnv.toml(1)