DIRENV-STDLIB 1 "2019" direnv "User Manuals"
============================================

NAME
----

direnv-stdlib - functions for the `.envrc`

SYNOPSIS
--------

`direnv stdlib`

DESCRIPTION
-----------

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.

STDLIB
------

### `has <command>`

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

Example:

    if has curl; then
      echo "Yes we do"
    fi

### `expand_path <rel_path> [<relative_to>]`

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

Example:

    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.

Example:

    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.

Example:

    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.

Example:

    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.

Example:

    # 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 when searching from the parent directory up to /.

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 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 it's 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.

Example:

    direnv_load opam-env 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*.

Example:

    pwd
    # 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

Example:

    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:

    CPATH
    LD_LIBRARY_PATH
    LIBRARY_PATH
    MANPATH
    PATH
    PKG_CONFIG_PATH

Example:

    ./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).

Examples:

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

### `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 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.

Example:

    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 environment`.

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

See https://www.gnu.org/software/guix/manual/html_node/Invoking-guix-environment.html

### `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:

- $NODE_VERSIONS (required)
  Points to a folder that contains all the installed Node versions. That
  folder must exist.

- $NODE_VERSION_PREFIX (optional) [default="node-v"]
  Overrides the default version prefix.

### `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:

- any command in a pipeline returns a non-zero exit status that is not
  otherwise handled as part of `if`, `while`, or `until` tests,
  return value negation (`!`), or part of a boolean (`&&` or `||`)
  chain.
- any variable that has not explicitly been set or declared (with
  either `declare` or `local`) is referenced.

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

Example (Whole Script):

    strict_env
    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):

    unstrict_env
    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
    fi

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


COPYRIGHT
---------

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

SEE ALSO
--------

direnv(1), direnv.toml(1)
