Polyglot runtime manager (asdf rust clone)

The following shows using rtx to install nodejs and jq into a project using a .tool-versions file. hyperfine is used to show the performance using rtx vs asdf. (See Performance). Note that calling which node gives us a real path to the binary, not a shim.

• asdf-compatible - rtx is compatible with asdf plugins and .tool-versions files. It can be used as a drop-in replacement.
• Polyglot - compatible with any language, so no more figuring out how nvm, nodenv, pyenv, etc work individually—just use 1 tool.
• Fast - rtx is written in Rust and is very fast. 20x-200x faster than asdf.
• No shims - shims (used by asdf) cause problems, they break which node, and add overhead. We don't use them by default.
• Better UX - asdf is full of strange UX decisions (like asdf plugin add but also asdf install). We've taken care to make rtx easy to use.
• Fuzzy matching and aliases - no need to specify exact version numbers like with asdf.
• One command install - No need to manually install each plugin, just run rtx install and it will install all the plugins you need.
• Arbitrary env vars - Set custom env vars when in a project directory like NODE_ENV=production or AWS_PROFILE=staging.

Install rtx (other methods here):

$ curl https://rtx.pub/rtx-latest-macos-arm64 > ~/bin/rtx
$ chmod +x ~/bin/rtx
$ rtx --version
rtx 1.23.1

Hook rtx into to your shell. This will automatically add ~/bin to PATH if it isn't already. (choose one, and open a new shell session for the changes to take effect):

$ echo 'eval "$(~/bin/rtx activate bash)"' >> ~/.bashrc
$ echo 'eval "$(~/bin/rtx activate zsh)"' >> ~/.zshrc
$ echo '~/bin/rtx activate fish | source' >> ~/.config/fish/config.fish

Warning

If you use direnv with layout python or other logic that needs to reference rtx runtimes inside of an .envrc, see the direnv section below.

Install a runtime and set it as the default:

$ rtx install nodejs@18
$ rtx global nodejs@18
$ node -v
v18.10.9

Note

rtx install is optional, rtx global will prompt to install the runtime if it's not already installed. This is configurable in ~/.config/rtx/config.toml.

New developer? Try reading the Beginner's Guide for a gentler introduction.

rtx is a tool for managing programming language and tool versions. For example, use this to install a particular version of node.js and ruby for a project. Using rtx activate, you can have your shell automatically switch to the correct node and ruby versions when you cd into the project's directory. Other projects on your machine can use a different set of versions.

rtx is inspired by asdf and uses asdf's vast plugin ecosystem under the hood. However, it is much faster than asdf and has a more friendly user experience. For more on how rtx compares to asdf, see below. The goal of this project was to create a better front-end to asdf.

It uses the same .tool-versions file that asdf uses. It's also compatible with idiomatic version files like .node-version and .ruby-version. See Legacy Version Files below.

Come chat about rtx on discord.

Typically, developers would use rtx to manage versions of their dev tools for local development. The main purpose of using rtx is being able to have different versions of languages for different projects on the same machine. (For example, one project might require python-3.10 and another python-3.11).

Using rtx in production is less common but still a supported use-case. Usually a production setup won't have different directories for different projects with different dev tool requirements. However using .tool-versions/.rtx.toml config in production provides parity with local development so rtx is still definitely useful in production setups. See the GitHub Action for an example of using rtx in production.

rtx installs as a shell extension (e.g. rtx activate zsh) that sets the PATH environment variable to point your shell to the correct runtime binaries. When you cd into a directory containing a .tool-versions file, rtx will automatically activate the correct versions.

Every time your prompt starts it will call rtx hook-env to fetch new environment variables. This should be very fast and it exits early if the the directory wasn't changed or the .tool-versions files haven't been updated. On my machine this takes 4ms in the fast case, 14ms in the slow case. See Performance for more on this topic.

Unlike asdf which uses shim files to dynamically locate runtimes when they're called, rtx modifies PATH ahead of time so the runtimes are called directly. This is not only faster since it avoids any overhead, but it also makes it so commands like which node work as expected. This also means there isn't any need to run asdf reshim after installing new runtime binaries.

rtx does not directly install runtimes. Instead, it uses asdf plugins to install runtimes. See plugins below.

rtx install [email protected]       Install a specific version number
rtx install [email protected]         Install a fuzzy version number
rtx local nodejs@18             Use node-18.x in current project
rtx global nodejs@18            Use node-18.x as default

rtx install nodejs              Install the version specified in .tool-versions
rtx local nodejs@latest         Use latest node in current directory
rtx global nodejs@system        Use system node as default

rtx x nodejs@18 -- node app.js  Run `node app.js` with the PATH pointing to node-18.x

Note that it isn't necessary for rtx to be on PATH. If you run the activate script in your rc file, rtx will automatically add itself to PATH.

$ curl https://rtx.pub/install.sh | sh

or if you're allergic to | sh:

$ curl https://rtx.pub/rtx-latest-macos-arm64 > /usr/local/bin/rtx

It doesn't matter where you put it. So use ~/bin, /usr/local/bin, ~/.local/share/rtx/bin/rtx or whatever.

Supported architectures:

• x64
• arm64

Supported platforms:

• macos
• linux

If you need something else, compile it with cargo.

There are 2 ways to install rtx with Homebrew. The recommended method is to use the custom tap which will always contain the latest release.

$ brew install jdxcode/tap/rtx

Alternatively, you can use the built-in tap (homebrew-core), which will be updated once Homebrew maintainers merge the PR for a new release:

$ brew install rtx

Build from source with Cargo:

$ cargo install rtx-cli

Do it faster with cargo-binstall:

$ cargo install cargo-binstall
$ cargo binstall rtx-cli

Build from the latest commit in main:

$ cargo install rtx-cli --git https://github.com/jdxcode/rtx --branch main

rtx is available on npm as precompiled binaries. This isn't a node.js package, just distributed via npm. It can be useful for JS projects that want to setup rtx via package.json or npx.

$ npm install -g rtx-cli

Or use npx if you just want to test it out for a single command without fully installing:

$ npx rtx-cli exec [email protected] -- python some_script.py

Download the latest release from GitHub.

$ curl https://github.com/jdxcode/rtx/releases/download/v1.23.1/rtx-v1.23.1-linux-x64 | tar -xJv
$ mv rtx/bin/rtx /usr/local/bin

For installation on Ubuntu/Debian:

wget -qO - https://rtx.pub/gpg-key.pub | gpg --dearmor | sudo tee /usr/share/keyrings/rtx-archive-keyring.gpg 1> /dev/null
echo "deb [signed-by=/usr/share/keyrings/rtx-archive-keyring.gpg arch=amd64] https://rtx.pub/deb stable main" | sudo tee /etc/apt/sources.list.d/rtx.list
sudo apt update
sudo apt install -y rtx

Warning

If you're on arm64 you'll need to run the following:

echo "deb [signed-by=/usr/share/keyrings/rtx-archive-keyring.gpg arch=arm64] https://rtx.pub/deb stable main" | sudo tee /etc/apt/sources.list.d/rtx.list

For Fedora, CentOS, Amazon Linux, RHEL and other dnf-based distributions:

dnf install -y dnf-plugins-core
dnf config-manager --add-repo https://rtx.pub/rpm/rtx.repo
dnf install -y rtx

yum install -y yum-utils
yum-config-manager --add-repo https://rtx.pub/rpm/rtx.repo
yum install -y rtx

For Alpine Linux:

apk add rtx --repository=http://dl-cdn.alpinelinux.org/alpine/edge/testing/

For Arch Linux:

git clone https://aur.archlinux.org/rtx.git
cd rtx
makepkg -si

For NixOS or those using the Nix package manager:

{
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
    flake-utils.url = "github:numtide/flake-utils";
    rtx-flake = {
      url = "github:chadac/rtx/add-nix-flake";
      inputs.nixpkgs.follows = "nixpkgs";
      inputs.flake-utils.follows = "flake-utils";
    };
  };

  outputs = { self, nixpkgs, flake-utils, rtx-flake }:
    flake-utils.lib.eachDefaultSystem(system:
      let
        pkgs = import nixpkgs {
          inherit system;
          overlays = [ rtx-flake.overlay ];
        };
      in {
        devShells.default = pkgs.mkShell {
          name = "my-dev-env";
          nativeBuildInputs = with pkgs; [
            rtx
          ];
        };
      }
    );
}

You can also import the package directly using rtx-flake.packages.${system}.rtx. It supports all default Nix systems.

$ echo 'eval "$(rtx activate bash)"' >> ~/.bashrc

$ echo 'rtx activate fish | source' >> ~/.config/fish/config.fish

Since .xsh files are not compiled you may shave a bit off startup time by using a pure Python import: add the code below to, for example, ~/.config/xonsh/rtx.py config file and import rtx it in ~/.config/xonsh/rc.xsh:

from pathlib        	import Path
from xonsh.built_ins	import XSH

ctx = XSH.ctx
rtx_init = subprocess.run([Path('~/bin/rtx').expanduser(),'activate','xonsh'],capture_output=True,encoding="UTF-8").stdout
XSH.builtins.execx(rtx_init,'exec',ctx,filename='rtx')

Or continue to use rc.xsh/.xonshrc:

echo 'execx($(~/bin/rtx activate xonsh))' >> ~/.config/xonsh/rc.xsh # or ~/.xonshrc

Given that rtx replaces both shell env $PATH and OS environ PATH, watch out that your configs don't have these two set differently (might throw os.environ['PATH'] = xonsh.built_ins.XSH.env.get_detyped('PATH') at the end of a config to make sure they match)

Adding a new shell is not hard at all since very little shell code is in this project. See here for how the others are implemented. If your shell isn't currently supported I'd be happy to help you get yours integrated.

Use rtx implode to uninstall rtx. This will remove the rtx binary and all of its data. Use rtx implode --help for more information.

Alternatively, manually remove the following directories to fully clean up:

• ~/.local/share/rtx (can also be RTX_DATA_DIR or XDG_DATA_HOME/rtx)
• ~/.config/rtx (can also be RTX_CONFIG_DIR or XDG_CONFIG_HOME/rtx)
• on Linux: ~/.cache/rtx (can also be RTX_CACHE_DIR or XDG_CACHE_HOME/rtx)
• on macOS: ~/Library/Caches/rtx (can also be RTX_CACHE_DIR)

The .tool-versions file is used to specify the runtime versions for a project. An example of this is:

nodejs      18.0.0       # comments are allowed
ruby        3            # can be fuzzy version
shellcheck  latest       # also supports "latest"
jq          1.6
erlang      ref:master   # compile from vcs ref
golang      prefix:1.19  # uses the latest 1.19.x version—needed in case "1.19" is an exact match
shfmt       path:./shfmt # use a custom runtime
nodejs      lts          # use lts version of nodejs (not supported by all plugins)
nodejs      lts!-2       # install 2 versions behind the latest lts (e.g.: 16 if lts is 18)
python      latest!-0.1  # install python-3.10 if the latest is 3.11

Create .tool-versions files manually, or use rtx local to create them automatically. See the asdf docs for more info on this file format.

rtx supports "legacy version files" just like asdf. They're language-specific files like .node-version and .python-version. These are ideal for setting the runtime version of a project without forcing other developers to use a specific tool like rtx/asdf.

They support aliases, which means you can have an .nvmrc file with lts/hydrogen and it will work in rtx and nvm. Here are some of the supported legacy version files:

In rtx these are enabled by default. You can disable them with rtx settings set legacy_version_file false. There is a performance cost to having these when they're parsed as it's performed by the plugin in bin/parse-version-file. However these are cached so it's not a huge deal. You may not even notice.

Note

asdf calls these "legacy version files" so we do too. I think this is a bad name since it implies that they shouldn't be used—which is definitely not the case IMO. I prefer the term "idiomatic" version files since they're version files not specific to asdf/rtx and can be used by other tools. (.nvmrc being a notable exception, which is tied to a specific tool.)

rtx can be configured in ~/.config/rtx/config.toml. The following options are available (defaults shown):

[settings]
# whether to prompt to install plugins and runtimes if they're not already installed
missing_runtime_behavior = 'prompt' # other options: 'ignore', 'warn', 'prompt', 'autoinstall'

# plugins can read the versions files used by other version managers (if enabled by the plugin)
# for example, .nvmrc in the case of nodejs's nvm
legacy_version_file = true         # enabled by default (different than asdf)

# configure `rtx install` to always keep the downloaded archive
always_keep_download = false        # deleted after install by default

# configure how frequently (in minutes) to fetch updated plugin repository changes
# this is updated whenever a new runtime is installed
# (note: this isn't currently implemented but there are plans to add it: https://github.com/jdxcode/rtx/issues/128)
plugin_autoupdate_last_check_duration = '1 week' # set to 0 to disable updates

verbose = false     # set to true to see full installation output, see `RTX_VERBOSE`
asdf_compat = false # set to true to ensure .tool-versions will be compatible with asdf, see `RTX_ASDF_COMPAT`
jobs = 4            # number of plugins or runtimes to install in parallel. The default is `4`.
raw = false         # set to true to directly pipe plugins to stdin/stdout/stderr

shorthands_file = '~/.config/rtx/shorthands.toml' # path to the shorthands file, see `RTX_SHORTHANDS_FILE`
disable_default_shorthands = false # disable the default shorthands, see `RTX_DISABLE_DEFAULT_SHORTHANDS`

experimental = false # enable experimental features such as shims
shims_dir = '~/.local/share/rtx/shims' # [experimental] directory where shims are stored

[alias.nodejs]
my_custom_node = '18'  # makes `rtx install nodejs@my_custom_node` install node-18.x
                       # this can also be specified in a plugin (see below in "Aliases")

These settings can also be managed with rtx settings ls|get|set|unset.

.rtx.toml is a new config file that replaces both the global config and the .tool-versions file. Think of ~/.config/rtx/config.toml as just a special .rtx.toml which is used from any directory on the machine.

It allows for functionality that is not possible with .tool-versions, such as:

• setting arbitrary env vars while inside the directory
• passing options to plugins like virtualenv='.venv' for rtx-python.
• specifying plugin repo url for custom plugins so it does not need to be added manually

Here is what the config looks like:

[env]
NODE_ENV = 'production' # supports arbitrary env vars so rtx can be used like dotenv

[tools]
# specify single or multiple versions
terraform = '1.0.0'
erlang = ['23.3', '24.0']

# supports everything you can do with .tool-versions currently
nodejs = ['16', 'prefix:18', 'ref:master', 'path:~/.nodes/14']

# send arbitrary options to the plugin, passed as:
# RTX_TOOL_OPTS__VENV=.venv
# RTX_TOOL_OPTS__DEFAULT_PACKAGES__0=ansible
# RTX_TOOL_OPTS__DEFAULT_PACKAGES__1=pipenv
python = { version = '3.10', venv = '.venv', default_packages = ['ansible', 'pipenv'] }

[plugins]
# specify a custom repo url
# note this will only be used if the plugin does not already exist
python = 'https://github.com/jdxcode/rtx-python'

[settings] # project-local settings
verbose = true
missing_runtime_behavior = 'warn'
shims_dir = '~/.rtx/shims'

[alias.nodejs] # project-local aliases
my_custom_node = '18'

.rtx.toml is currently experimental and may change in minor versions of rtx. It does not require setting experimental = true in the global config in part because this config can itself contain the setting for experimental.

rtx can also be configured via environment variables. The following options are available:

This is the same as the missing_runtime_behavior config option in ~/.config/rtx/config.toml.

$ RTX_MISSING_RUNTIME_BEHAVIOR=ignore rtx install nodejs@18
$ RTX_NODEJS_VERSION=18 rtx exec -- node --version

This is the directory where rtx stores its data. The default is ~/.local/share/rtx.

This is the directory where rtx stores cache. The default is ~/.cache/rtx on Linux and ~/Library/Caches/rtx on macOS.

This is the path to the config file. The default is ~/.config/rtx/config.toml. (Or $XDG_CONFIG_HOME/config.toml if that is set)

Set to something other than ".tool-versions" to have rtx look for configuration with alternate names.

Set to something other than ".rtx.toml" to have rtx look for configuration with alternate names.

This is the same as RTX_DEFAULT_TOOL_VERSIONS_FILENAME but for .rtx.toml format.

Set the version for a runtime. For example, RTX_NODEJS_VERSION=18 will use [email protected] regardless of what is set in .tool-versions.

Plugins can read the versions files used by other version managers (if enabled by the plugin) for example, .nvmrc in the case of nodejs's nvm.

Set to 1 to use default to using .rtx.toml in rtx local instead of .tool-versions for configuration.

Can also use RTX_DEBUG=1, RTX_TRACE=1, and RTX_QUIET=1. These adjust the log output to the screen.

Output logs to a file.

Same as RTX_LOG_LEVEL but for the log file output level. This is useful if you want to store the logs but not have them litter your display.

This shows the installation output during rtx install and rtx plugin install. This should likely be merged so it behaves the same as RTX_DEBUG=1 and we don't have 2 configuration for the same thing, but for now it is it's own config.

Only output .tool-versions files in rtx local|global which will be usable by asdf.

Set the number plugins or runtimes to install in parallel. The default is 4.

Set to "1" to directly pipe plugin scripts to stdin/stdout/stderr. By default stdin is disabled because when installing a bunch of plugins in parallel you won't see the prompt. Use this if a plugin accepts input or otherwise does not seem to be installing correctly.

Sets RTX_JOBS=1 because only 1 plugin script can be executed at a time.

Use a custom file for the shorthand aliases. This is useful if you want to share plugins within an organization.

The file should be in toml format:

elixir = "https://github.com/my-org/rtx-elixir.git"
nodejs = "https://github.com/my-org/rtx-nodejs.git"

Disables the shorthand aliases for installing plugins. You will have to specify full urls when installing plugins, e.g.: rtx plugin install nodejs https://github.com/asdf-vm/asdf-nodejs.git

Currently this disables the following:

• --fuzzy as default behavior (rtx local nodejs@18 will save exact version)

If a release is 12 months old, it will show a warning message every time it launches:

rtx has not been updated in over a year. Please update to the latest version.

You likely do not want to be using rtx if it is that old. I'm doing this instead of autoupdating. If, for some reason, you want to stay on some old version, you can hide this message with RTX_HIDE_OUTDATED_BUILD=1.

Enables experimental features such as shims.

Set a directory to output shims when running rtx reshim. Requires experimental = true.

rtx supports aliasing the versions of runtimes. One use-case for this is to define aliases for LTS versions of runtimes. For example, you may want to specify lts/hydrogen as the version for [email protected]. So you can use the runtime with nodejs lts/hydrogen in .tool-versions.

User aliases can be created by adding an alias.<PLUGIN> section to ~/.config/rtx/config.toml:

[alias.nodejs]
my_custom_18 = '18'

Plugins can also provide aliases via a bin/list-aliases script. Here is an example showing node.js versions:

#!/usr/bin/env bash

echo "lts/hydrogen 18"
echo "lts/gallium 16"
echo "lts/fermium 14"

Note:

Because this is rtx-specific functionality not currently used by asdf it isn't likely to be in any plugin currently, but plugin authors can add this script without impacting asdf users.

rtx uses asdf's plugin ecosystem under the hood. These plugins contain shell scripts like bin/install (for installing) and bin/list-all (for listing all of the available versions).

See https://github.com/asdf-vm/asdf-plugins for the list of built-in plugins shorthands. See asdf's Create a Plugin for how to create your own or just learn more about how they work.

rtx has support for "plugin options" which is configuration specified in .rtx.toml to change behavior of plugins. One example of this is virtualenv on python runtimes:

[tools]
python = {version='3.11', virtualenv='.venv'}

This will be passed to all plugin scripts as RTX_TOOL_OPTS__VIRTUALENV=.venv. The user can specify any option and it will be passed to the plugin in that format.

Currently this only supports simple strings, but we can make it compatible with more complex types (arrays, tables) fairly easily if there is a need for it.

rtx is currently a new project and is under very rapid development. Slight behavior changes may occur between releases. Features marked as "experimental" may change significantly or be removed entirely.

Starting June 1, 2023*, rtx will move to Calver versioning (2023.6.1). After the move to Calver, rtx's design will become mostly permanent and you will be able to rely on its behavior for the long term. Breaking changes will be few but when they do happen, they will be communicated in the CLI with plenty of notice whenever possible.

Rather than have semver major releases to communicate change in large releases, new functionality and changes can be opted-into with settings like experimental = true. This way plugin authors and users can test out new functionality immediately without waiting for a major release.

The numbers in Calver (YYYY.MM.RELEASE) simply represent the date of the release—not compatibility or how many new features were added. Each release will be small and incremental.

*This plan is tentative and the details may change, but the rough idea of making many changes now so we can have stability later is the goal.

When we switch to Calver, we'll immediately make some notable design changes to rtx. This will be the first and last time that such a change is made and I actually want to make sure we make as many as we can—because we'll be stuck with these decisions.

Here are a list of the changes that will be made:

• rtx local will default to creating .rtx.toml instead of .tool-versions. (If the config already exists the format will be preserved.)
• rtx global will modify ~/.config/rtx/config.toml instead of ~/.tool-versions. This path can be changed with RTX_CONFIG_FILE.
• ~/.tool-versions will become simply another .tool-versions instead of being a special file that is read anywhere such as from /tmp.
• (more to be added)

Initializes rtx in the current shell

This should go into your shell's rc file.
Otherwise, it will only take effect in the current session.
(e.g. ~/.bashrc)

Usage: activate [OPTIONS] [SHELL_TYPE]

Arguments:
  [SHELL_TYPE]
          Shell type to generate the script for
          
          [possible values: bash, fish, xonsh, zsh]

Options:
      --status
          Show "rtx: <PLUGIN>@<VERSION>" message when changing directories

Examples:
    $ eval "$(rtx activate bash)"
    $ eval "$(rtx activate zsh)"
    $ rtx activate fish | source
    $ execx($(rtx activate xonsh))

Show an alias for a plugin

This is the contents of an alias.<PLUGIN> entry in ~/.config/rtx/config.toml

Usage: get <PLUGIN> <ALIAS>

Arguments:
  <PLUGIN>
          The plugin to show the alias for

  <ALIAS>
          The alias to show

Examples:
  $ rtx alias get nodejs lts/hydrogen
  18.0.0

List aliases
Shows the aliases that can be specified.
These can come from user config or from plugins in `bin/list-aliases`.

For user config, aliases are defined like the following in `~/.config/rtx/config.toml`:

  [alias.nodejs]
  lts = "18.0.0"

Usage: ls [OPTIONS]

Options:
  -p, --plugin <PLUGIN>
          Show aliases for <PLUGIN>

Examples:
  $ rtx aliases
  nodejs    lts/hydrogen   18.0.0

Add/update an alias for a plugin

This modifies the contents of ~/.config/rtx/config.toml

Usage: set <PLUGIN> <ALIAS> <VALUE>

Arguments:
  <PLUGIN>
          The plugin to set the alias for

  <ALIAS>
          The alias to set

  <VALUE>
          The value to set the alias to

Examples:
  $ rtx alias set nodejs lts/hydrogen 18.0.0

Clears an alias for a plugin

This modifies the contents of ~/.config/rtx/config.toml

Usage: unset <PLUGIN> <ALIAS>

Arguments:
  <PLUGIN>
          The plugin to remove the alias from

  <ALIAS>
          The alias to remove

Examples:
  $ rtx alias unset nodejs lts/hydrogen

List all the active runtime bin paths

Usage: bin-paths

Deletes all cache files in rtx

Usage: clear

Generate shell completions

Usage: complete --shell <SHELL>

Options:
  -s, --shell <SHELL>
          shell type
          
          [possible values: bash, elvish, fish, powershell, zsh]

Examples:
  $ rtx complete -s bash > /etc/bash_completion.d/rtx
  $ rtx complete -s zsh  > /usr/local/share/zsh/site-functions/_rtx
  $ rtx complete -s fish > ~/.config/fish/completions/rtx.fish

Shows current active and installed runtime versions

This is similar to `rtx ls --current`, but this only shows the runtime
and/or version. It's designed to fit into scripts more easily.

Usage: current [PLUGIN]

Arguments:
  [PLUGIN]
          Plugin to show versions of e.g.: ruby, nodejs

Examples:
  # outputs `.tool-versions` compatible format
  $ rtx current
  python 3.11.0 3.10.0
  shfmt 3.6.0
  shellcheck 0.9.0
  nodejs 18.13.0

  $ rtx current nodejs
  18.13.0

  # can output multiple versions
  $ rtx current python
  3.11.0 3.10.0

Disable rtx for current shell session

This can be used to temporarily disable rtx in a shell session.

Usage: deactivate

Examples:
  $ rtx deactivate bash
  $ rtx deactivate zsh
  $ rtx deactivate fish
  $ execx($(rtx deactivate xonsh))

Output direnv function to use rtx inside direnv

See https://github.com/jdxcode/rtx#direnv for more information

Because this generates the legacy files based on currently installed plugins,
you should run this command after installing new plugins. Otherwise
direnv may not know to update environment variables when legacy file versions change.

Usage: activate

Examples:
  $ rtx direnv activate > ~/.config/direnv/lib/use_rtx.sh
  $ echo 'use rtx' > .envrc
  $ direnv allow

Check rtx installation for possible problems.

Usage: doctor

Examples:
  $ rtx doctor
  [WARN] plugin nodejs is not installed

Exports env vars to activate rtx a single time

Use this if you don't want to permanently install rtx. It's not necessary to
use this if you have `rtx activate` in your shell rc file.

Usage: env [OPTIONS] [RUNTIME]...

Arguments:
  [RUNTIME]...
          Runtime version to use

Options:
  -s, --shell <SHELL>
          Shell type to generate environment variables for
          
          [possible values: bash, fish, xonsh, zsh]

Examples:
  $ eval "$(rtx env -s bash)"
  $ eval "$(rtx env -s zsh)"
  $ rtx env -s fish | source
  $ execx($(rtx env -s xonsh))

Execute a command with runtime(s) set

use this to avoid modifying the shell session or running ad-hoc commands with the rtx runtimes
set.

Runtimes will be loaded from .tool-versions, though they can be overridden with <RUNTIME> args
Note that only the plugin specified will be overridden, so if a `.tool-versions` file
includes "nodejs 18" but you run `rtx exec [email protected]`; it will still load nodejs@18.

The "--" separates runtimes from the commands to pass along to the subprocess.

Usage: exec [OPTIONS] [RUNTIME]... [-- <COMMAND>...]

Arguments:
  [RUNTIME]...
          Runtime(s) to start e.g.: nodejs@18 [email protected]

  [COMMAND]...
          Command string to execute (same as --command)

Options:
  -c, --command <C>
          Command string to execute

Examples:
  rtx exec nodejs@18 -- node ./app.js  # launch app.js using node-18.x
  rtx x nodejs@18 -- node ./app.js     # shorter alias

  # Specify command as a string:
  rtx exec nodejs@18 [email protected] --command "node -v && python -V"

Sets/gets the global runtime version(s)

Displays the contents of ~/.tool-versions after writing.
The file is `$HOME/.tool-versions` by default. It can be changed with `$RTX_CONFIG_FILE`.
If `$RTX_CONFIG_FILE` is set to anything that ends in `.toml`, it will be parsed as `.rtx.toml`.
Otherwise, it will be parsed as a `.tool-versions` file.
A future v2 release of rtx will default to using `~/.config/rtx/config.toml` instead.

Use `rtx local` to set a runtime version locally in the current directory.

Usage: global [OPTIONS] [RUNTIME]...

Arguments:
  [RUNTIME]...
          Runtime(s) to add to .tool-versions
          e.g.: nodejs@18
          If this is a single runtime with no version, the current value of the global
          .tool-versions will be displayed

Options:
      --pin
          Save exact version to `~/.tool-versions`
          e.g.: `rtx local --pin nodejs@18` will save `nodejs 18.0.0` to ~/.tool-versions

      --fuzzy
          Save fuzzy version to `~/.tool-versions`
          e.g.: `rtx local --fuzzy nodejs@18` will save `nodejs 18` to ~/.tool-versions
          this is the default behavior unless RTX_ASDF_COMPAT=1

      --remove <PLUGIN>
          Remove the plugin(s) from ~/.tool-versions

      --path
          Get the path of the global config file

Examples:
  # set the current version of nodejs to 18.x
  # will use a fuzzy version (e.g.: 18) in .tool-versions file
  $ rtx global --fuzzy nodejs@18

  # set the current version of nodejs to 18.x
  # will use a precise version (e.g.: 18.0.0) in .tool-versions file
  $ rtx global --pin nodejs@18

  # show the current version of nodejs in ~/.tool-versions
  $ rtx global nodejs
  18.0.0

Removes rtx CLI and all related data

Skips config directory by default.

Usage: implode [OPTIONS]

Options:
      --config
          Also remove config directory

      --dry-run
          List directories that would be removed without actually removing them

Install a runtime

This will install a runtime to `~/.local/share/rtx/installs/<PLUGIN>/<VERSION>`
It won't be used simply by being installed, however.
For that, you must set up a `.tool-version` file manually or with `rtx local/global`.
Or you can call a runtime explicitly with `rtx exec <PLUGIN>@<VERSION> -- <COMMAND>`.

Runtimes will be installed in parallel. To disable, set `--jobs=1` or `RTX_JOBS=1`

Usage: install [OPTIONS] [RUNTIME]...

Arguments:
  [RUNTIME]...
          Runtime(s) to install e.g.: nodejs@18

Options:
  -p, --plugin <PLUGIN>
          Only install runtime(s) for <PLUGIN>

  -f, --force
          Force reinstall even if already installed

  -v, --verbose...
          Show installation output

Examples:
  $ rtx install [email protected]  # install specific nodejs version
  $ rtx install nodejs@18      # install fuzzy nodejs version
  $ rtx install nodejs         # install version specified in .tool-versions or .rtx.toml
  $ rtx install                # installs all runtimes specified in .tool-versions or .rtx.toml

Gets the latest available version for a plugin

Usage: latest <RUNTIME>

Arguments:
  <RUNTIME>
          Runtime to get the latest version of

Examples:
  $ rtx latest nodejs@18  # get the latest version of nodejs 18
  18.0.0

  $ rtx latest nodejs     # get the latest stable version of nodejs
  20.0.0

Sets/gets tool version in local .tool-versions or .rtx.toml

Use this to set a tool's version when within a directory
Use `rtx global` to set a runtime version globally
This uses `.tool-version` by default unless there is a `.rtx.toml` file or if `RTX_USE_TOML`
is set. A future v2 release of rtx will default to using `.rtx.toml`.

Usage: local [OPTIONS] [RUNTIME]...

Arguments:
  [RUNTIME]...
          Runtimes to add to .tool-versions/.rtx.toml
          e.g.: nodejs@18
          if this is a single runtime with no version,
          the current value of .tool-versions/.rtx.toml will be displayed

Options:
  -p, --parent
          Recurse up to find a .tool-versions file rather than using the current directory only
          by default this command will only set the runtime in the current directory ("$PWD/.tool-versions")

      --pin
          Save exact version to `.tool-versions`
          e.g.: `rtx local --pin nodejs@18` will save `nodejs 18.0.0` to .tool-versions

      --fuzzy
          Save fuzzy version to `.tool-versions` e.g.: `rtx local --fuzzy nodejs@18` will save `nodejs 18` to .tool-versions This is the default behavior unless RTX_ASDF_COMPAT=1

      --remove <PLUGIN>
          Remove the plugin(s) from .tool-versions

      --path
          Get the path of the config file

Examples:
  # set the current version of nodejs to 18.x for the current directory
  # will use a precise version (e.g.: 18.0.0) in .tool-versions file
  $ rtx local nodejs@18

  # set nodejs to 18.x for the current project (recurses up to find .tool-versions)
  $ rtx local -p nodejs@18

  # set the current version of nodejs to 18.x for the current directory
  # will use a fuzzy version (e.g.: 18) in .tool-versions file
  $ rtx local --fuzzy nodejs@18

  # removes nodejs from .tool-versions
  $ rtx local --remove=nodejs

  # show the current version of nodejs in .tool-versions
  $ rtx local nodejs
  18.0.0

List installed runtime versions

The "arrow (->)" indicates the runtime is installed, active, and will be used for running commands.
(Assuming `rtx activate` or `rtx env` is in use).

Usage: ls [OPTIONS]

Options:
  -p, --plugin <PLUGIN>
          Only show runtimes from [PLUGIN]

  -c, --current
          Only show runtimes currently specified in .tool-versions

      --parseable
          Output in an easily parseable format
          
          [short aliases: x]

      --json
          Output in json format

Examples:
  $ rtx ls
  ⏵  nodejs     18.0.0 (set by ~/src/myapp/.tool-versions)
  ⏵  python     3.11.0 (set by ~/.tool-versions)
     python     3.10.0

  $ rtx ls --current
  ⏵  nodejs     18.0.0 (set by ~/src/myapp/.tool-versions)
  ⏵  python     3.11.0 (set by ~/.tool-versions)

  $ rtx ls --parseable
  nodejs 18.0.0
  python 3.11.0

  $ rtx ls --json
  {
    "nodejs": [
      {
        "version": "18.0.0",
        "install_path": "/Users/jdx/.rtx/installs/nodejs/18.0.0",
        "source": {
          "type": ".rtx.toml",
          "path": "/Users/jdx/.rtx.toml"
        }
      }
    ],
    "python": [...]
  }

List runtime versions available for install

note that these versions are cached for commands like `rtx install nodejs@latest`
however _this_ command will always clear that cache and fetch the latest remote versions

Usage: ls-remote <PLUGIN> [PREFIX]

Arguments:
  <PLUGIN>
          Plugin to get versions for

  [PREFIX]
          The version prefix to use when querying the latest version
          same as the first argument after the "@"

Examples:
  $ rtx ls-remote nodejs
  18.0.0
  20.0.0

  $ rtx ls-remote nodejs@18
  18.0.0
  18.1.0

  $ rtx ls-remote nodejs 18
  18.0.0
  18.1.0

Install a plugin

note that rtx automatically can install plugins when you install a runtime
e.g.: `rtx install nodejs@18` will autoinstall the nodejs plugin

This behavior can be modified in ~/.config/rtx/config.toml

Usage: install [OPTIONS] [NAME] [GIT_URL]

Arguments:
  [NAME]
          The name of the plugin to install
          e.g.: nodejs, ruby
          Can specify multiple plugins: `rtx plugins install nodejs ruby python`

  [GIT_URL]
          The git url of the plugin

Options:
  -f, --force
          Reinstall even if plugin exists

  -a, --all
          Install all missing plugins
          This will only install plugins that have matching shorthands.
          i.e.: they don't need the full git repo url

  -v, --verbose...
          Show installation output

Examples:
  # install the nodejs via shorthand
  $ rtx plugins install nodejs

  # install the nodejs plugin using a specific git url
  $ rtx plugins install nodejs https://github.com/jdxcode/rtx-nodejs.git

  # install the nodejs plugin using the git url only
  # (nodejs is inferred from the url)
  $ rtx plugins install https://github.com/jdxcode/rtx-nodejs.git

  # install the nodejs plugin using a specific ref
  $ rtx plugins install nodejs http://github.com/jdxcode/rtx-nodejs.git#v1.0.0

List installed plugins

Can also show remotely available plugins to install.

Usage: ls [OPTIONS]

Options:
  -a, --all
          List all available remote plugins
          Same as `rtx plugins ls-remote`

  -u, --urls
          Show the git url for each plugin
          e.g.: https://github.com/asdf-vm/asdf-nodejs.git

Examples:
  $ rtx plugins ls
  nodejs
  ruby

  $ rtx plugins ls --urls
  nodejs                        https://github.com/asdf-vm/asdf-nodejs.git
  ruby                          https://github.com/asdf-vm/asdf-ruby.git

List all available remote plugins

These are fetched from https://github.com/asdf-vm/asdf-plugins

Examples:
  $ rtx plugins ls-remote


Usage: ls-remote [OPTIONS]

Options:
  -u, --urls
          Show the git url for each plugin e.g.: https://github.com/asdf-vm/asdf-nodejs.git

      --only-names
          Only show the name of each plugin by default it will show a "*" next to installed plugins

Removes a plugin

Usage: uninstall <PLUGIN>...

Arguments:
  <PLUGIN>...
          Plugin(s) to remove

Examples:
  $ rtx uninstall nodejs

Updates a plugin to the latest version

note: this updates the plugin itself, not the runtime versions

Usage: update [OPTIONS] [PLUGIN]...

Arguments:
  [PLUGIN]...
          Plugin(s) to update

Options:
  -a, --all
          Update all plugins

Examples:
  $ rtx plugins update --all        # update all plugins
  $ rtx plugins update nodejs       # update only nodejs
  $ rtx plugins update nodejs@beta  # specify a ref

Delete unused versions of tools

rtx tracks which config files have been used in ~/.local/share/rtx/tracked_config_files
Versions which are no longer the latest specified in any of those configs are deleted.
Versions installed only with environment variables (`RTX_<PLUGIN>_VERSION`) will be deleted,
as will versions only referenced on the command line (`rtx exec <PLUGIN>@<VERSION>`).

Usage: prune [OPTIONS] [PLUGINS]...

Arguments:
  [PLUGINS]...
          Prune only versions from these plugins

Options:
      --dry-run
          Do not actually delete anything

Examples:
  $ rtx prune --dry-run
  rm -rf ~/.local/share/rtx/versions/nodejs/18.0.0
  rm -rf ~/.local/share/rtx/versions/nodejs/18.0.1

[experimental] rebuilds the shim farm

this requires that the shims_dir is set

Usage: reshim

Examples:
  $ rtx settings set experimental true
  $ rtx settings set shims_dir ~/.rtx/shims
  $ rtx reshim
  $ ~/.rtx/shims/node -v
  v18.0.0

Updates rtx itself

Uses whatever package manager was used to install rtx or just downloads
a binary from GitHub Releases if rtx was installed manually.
Supports: standalone, brew, deb, rpm

Usage: self-update

Show a current setting

This is the contents of a single entry in ~/.config/rtx/config.toml

Note that aliases are also stored in this file
but managed separately with `rtx aliases get`

Usage: get <KEY>

Arguments:
  <KEY>
          The setting to show

Examples:
  $ rtx settings get legacy_version_file
  true

Show current settings

This is the contents of ~/.config/rtx/config.toml

Note that aliases are also stored in this file
but managed separately with `rtx aliases`

Usage: ls

Examples:
  $ rtx settings
  legacy_version_file = false

Add/update a setting

This modifies the contents of ~/.config/rtx/config.toml

Usage: set <KEY> <VALUE>

Arguments:
  <KEY>
          The setting to set

  <VALUE>
          The value to set

Examples:
  $ rtx settings set legacy_version_file true

Clears a setting

This modifies the contents of ~/.config/rtx/config.toml

Usage: unset <KEY>

Arguments:
  <KEY>
          The setting to remove

Examples:
  $ rtx settings unset legacy_version_file

Sets a tool version for the current shell session

Only works in a session where rtx is already activated.

Usage: shell [OPTIONS] [RUNTIME]...

Arguments:
  [RUNTIME]...
          Runtime version(s) to use

Options:
  -u, --unset
          Removes a previously set version

Examples:
  $ rtx shell nodejs@18
  $ node -v
  v18.0.0

Removes runtime versions

Usage: uninstall <RUNTIME>...

Arguments:
  <RUNTIME>...
          Runtime(s) to remove

Examples:
  $ rtx uninstall [email protected] # will uninstall specific version
  $ rtx uninstall nodejs        # will uninstall current nodejs version

Show rtx version

Usage: version

Display the installation path for a runtime

Must be installed.

Usage: where <RUNTIME>

Arguments:
  <RUNTIME>
          Runtime(s) to look up
          e.g.: ruby@3
          if "@<PREFIX>" is specified, it will show the latest installed version
          that matches the prefix
          otherwise, it will show the current, active installed version

Examples:
  # Show the latest installed version of nodejs
  # If it is is not installed, errors
  $ rtx where nodejs@18
  /home/jdx/.local/share/rtx/installs/nodejs/18.0.0

  # Show the current, active install directory of nodejs
  # Errors if nodejs is not referenced in any .tool-version file
  $ rtx where nodejs
  /home/jdx/.local/share/rtx/installs/nodejs/18.0.0

Shows the path that a bin name points to

Usage: which [OPTIONS] <BIN_NAME>

Arguments:
  <BIN_NAME>
          

Options:
      --plugin
          Show the plugin name instead of the path

      --version
          Show the version instead of the path

Examples:
  $ rtx which node
  /home/username/.local/share/rtx/installs/nodejs/18.0.0/bin/node
  $ rtx which node --plugin
  nodejs
  $ rtx which node --version
  18.0.0

You can make git ignore these files in 3 different ways:

• Adding .tool-versions to project's .gitignore file. This has the downside that you need to commit the change to the ignore file.
• Adding .tool-versions to project's .git/info/exclude. This file is local to your project so there is no need to commit it.
• Adding .tool-versions to global gitignore (core.excludesFile). This will cause git to ignore .tool-versions files in all projects. You can explicitly add one to a project if needed with git add --force .tool-versions.

First try setting RTX_DEBUG=1 or RTX_TRACE=1 and see if that gives you more information. You can also set RTX_LOG_FILE_LEVEL=debug RTX_LOG_FILE=/path/to/logfile to write logs to a file.

If something is happening with the activate hook, you can try disabling it and calling eval "$(rtx hook-env)" manually. It can also be helpful to use rtx env which will just output environment variables that would be set. Also consider using shims which can be more compatible.

If runtime installation isn't working right, try using the --raw flag which will install things in series and connect stdin/stdout/stderr directly to the terminal. If a plugin is trying to interact with you for some reason this will make it work.

Of course check the version of rtx with rtx --version and make sure it is the latest. Use rtx self-update to update it. rtx cache clean can be used to wipe the internal cache and rtx implode can be used to remove everything except config.

Before submitting a ticket, it's a good idea to test what you were doing with asdf. That way we can rule out if the issue is with rtx or if it's with a particular plugin. For example, if rtx install python@latest doesn't work, try running asdf install python latest to see if it's an issue with asdf-python.

Lastly, there is rtx doctor which will show diagnostic information and any warnings about issues detected with your setup. If you submit a bug report, please include the output of rtx doctor.

This is something we'd like to add! jdx#66

It's not a near-term goal and it would require plugin modifications, but it should be feasible.

Short answer: just set http_proxy and https_proxy environment variables. These should be lowercase.

rtx doesn't really do anything with http itself. The only exception to that is checking for new versions and rtx self-update. It uses git to clone plugins and the plugins themselves generally will download files with curl or wget.

However this is really up to the plugin. If you're having a proxy-related issue installing something you should post an issue on the plugin's repo.

e.g.: how does rtx plugin install nodejs know to fetch https://github.com/asdf-vm/asdf-nodejs?

asdf maintains an index of shorthands that rtx uses as a base. This is regularly updated every time that rtx has a release. This repository is stored directly into the codebase here. The bottom of that file contains modifications that rtx makes. For example, we add node which points to the same plugin as nodejs and change python to point to rtx-python which is a fork of asdf-python with some rtx features like virtualenv support.

Over time I suspect that more plugins will be forked like rtx-python as we're able to offer more rtx-specific enhancements.

First, just install rtx with rtx activate like in the getting started guide and remove asdf from your shell rc file.

Then you can just run rtx install in a directory with an asdf .tool-versions file and it will install the runtimes. You could attempt to avoid this by copying the internal directory from asdf over to rtx with cp -r ~/.asdf ~/.local/share/rtx. That should work because they use the same structure, however this isn't officially supported or regularly tested. Alternatively you can set RTX_DATA_DIR=~/.asdf and see what happens.

rtx should be able to read/install any .tool-versions file used by asdf. Any asdf plugin should be usable in rtx. The commands in rtx are slightly different, such as rtx install [email protected] vs asdf install nodejs 18.0.0—this is done so multiple tools can be specified at once. However, asdf-style syntax is still supported: (rtx install nodejs 18.0.0). This is the case for most commands, though the help for the command may say that asdf-style syntax is supported.

When in doubt, just try asdf syntax and see if it works. If it doesn't open a ticket. It may not be possible to support every command identically, but we should attempt to make things as consistent as possible.

This isn't important for usability reasons so much as making it so plugins continue to work that call asdf commands.

If you need to switch to/from asdf or work in a project with asdf users, you can set RTX_ASDF_COMPAT=1. That prevents rtx from writing .tool-versions files that will not be compatible with asdf. Also consider using .rtx.toml instead which won't conflict with asdf setups.

It's been reported that PATH doesn't work correctly with tmux. The fix seems to be calling hook-env right after activating:

eval "$(rtx activate bash)"
eval "$(rtx hook-env)"

This can also be useful if you need to use a runtime right away in an rc file. The default behavior of rtx activate is that it will only run hook-env when the shell is about to be displayed, not immediately after activating. Not calling hook-env immediately appears to work better with direnv.

rtx is mostly a clone of asdf, but there are notable areas where improvements have been made.

asdf made (what I consider) a poor design decision to use shims that go between a call to a runtime and the runtime itself. e.g.: when you call node it will call an asdf shim file ~/.asdf/shims/node, which then calls asdf exec, which then calls the correct version of node.

These shims have terrible performance, adding ~120ms to every runtime call. rtx does not use shims and instead updates PATH so that it doesn't have any overhead when simply calling binaries. These shims are the main reason that I wrote this. Note that in the demo gif at the top of this README that rtx isn't actually used when calling node -v for this reason. The performance is identical to running node without using rtx.

I don't think it's possible for asdf to fix these issues. The author of asdf did a great writeup of performance problems. asdf is written in bash which certainly makes it challenging to be performant, however I think the real problem is the shim design. I don't think it's possible to fix that without a complete rewrite.

rtx does call an internal command rtx hook-env every time the directory has changed, but because it's written in Rust, this is very quick—taking ~10ms on my machine. 4ms if there are no changes, 14ms if it's a full reload.

tl;dr: asdf adds overhead (~120ms) when calling a runtime, rtx adds a small amount of overhead (~10ms) when the prompt loads.

asdf only helps manage runtime executables. However, some tools are managed via environment variables (notably Java which switches via JAVA_HOME). This isn't supported very well in asdf and requires a separate shell extension just to manage.

However asdf plugins have a bin/exec-env script that is used for exporting environment variables like JAVA_HOME. rtx simply exports the environment variables from the bin/exec-env script in the plugin but places them in the shell for all commands. In asdf it only exports those commands when the shim is called. This means if you call java it will set JAVA_HOME, but not if you call some Java tool like mvn.

This means we're just using the existing plugin script but because rtx doesn't use shims it can be used for more things. It would be trivial to make a plugin that exports arbitrary environment variables like dotenv or direnv.

Some commands are the same in asdf but others have been changed. Everything that's possible in asdf should be possible in rtx but may use slightly different syntax. rtx has more forgiving commands, such as using fuzzy-matching, e.g.: rtx install nodejs@18. While in asdf you can run asdf install nodejs latest:18, you can't use latest:18 in a .tool-versions file or many other places. In rtx you can use fuzzy-matching everywhere.

asdf requires several steps to install a new runtime if the plugin isn't installed, e.g.:

$ asdf plugin add nodejs
$ asdf install nodejs latest:18
$ asdf local nodejs latest:18

In rtx this can all be done in a single step to set the local runtime version. If the plugin and/or runtime needs to be installed it will prompt:

I've found asdf to be particularly rigid and difficult to learn. It also made strange decisions like having asdf list all but asdf latest --all (why is one a flag and one a positional argument?). rtx makes heavy use of aliases so you don't need to remember if it's rtx plugin add nodejs or rtx plugin install nodejs. If I can guess what you meant, then I'll try to get rtx to respond in the right way.

That said, there are a lot of great things about asdf. It's the best multi-runtime manager out there and I've really been impressed with the plugin system. Most of the design decisions the authors made were very good. I really just have 2 complaints: the shims and the fact it's written in Bash.

Using rtx in CI/CD is a great way to synchronize tool versions for dev/build.

Use jdxcode/rtx-action:

- uses: jdxcode/rtx-action@v1
- run: node -v # will be the node version from `.tool-versions`

While the PATH design of rtx works great in most cases, there are some situations where shims are preferable. One example is when calling rtx binaries from an IDE.

To support this, there is experimental support for using rtx in a "shim" mode. To use:

$ rtx settings set experimental true
$ rtx settings set shims_dir ~/.rtx/shims
$ rtx i [email protected]
$ rtx reshim
$ ~/.rtx/shims/node -v
v18.0.0

direnv and rtx both manage environment variables based on directory. Because they both analyze the current environment variables before and after their respective "hook" commands are run, they can conflict with each other. As a result, there were a number of issues with direnv. However, we think we've mitigated these. If you find that rtx and direnv are not working well together, please comment on that ticket ideally with a good description of your directory layout so we can reproduce the problem.

If there are remaining issues, they're likely to do with the ordering of PATH. This means it would really only be a problem if you were trying to manage the same runtime with direnv and rtx. For example, you may use layout python in an .envrc but also be maintaining a .tool-versions file with python in it as well.

A more typical usage of direnv would be to set some arbitrary environment variables, or add unrelated binaries to PATH. In these cases, rtx will not interfere with direnv.

If you do encounter issues with rtx activate, or just want to use direnv in an alternate way, this is a simpler setup that's less likely to cause issues—at the cost of functionality.

This may be required if you want to use direnv's layout python with rtx. Otherwise there are situations where rtx will override direnv's PATH. use rtx ensures that direnv always has control.

To do this, first use rtx to build a use_rtx function that you can use in .envrc files:

$ rtx direnv activate > ~/.config/direnv/lib/use_rtx.sh

Now in your .envrc file add the following:

use rtx

direnv will now call rtx to export its environment variables. You'll need to make sure to add use_rtx to all projects that use rtx (or use direnv's source_up to load it from a subdirectory). You can also add use rtx to ~/.config/direnv/direnvrc.

Note that in this method direnv typically won't know to refresh .tool-versions files unless they're at the same level as a .envrc file. You'll likely always want to have a .envrc file next to your .tool-versions for this reason. To make this a little easier to manage, I encourage not actually using .tool-versions at all, and instead setting environment variables entirely in .envrc:

export RTX_NODEJS_VERSION=18.0.0
export RTX_PYTHON_VERSION=3.11

Of course if you use rtx activate, then these steps won't have been necessary and you can use rtx as if direnv was not used.

If you continue to struggle, you can also try using the experimental shims feature.

While making rtx compatible with direnv is, and will always be a major goal of this project, I also want rtx to be capable of replacing direnv if needed. This is why rtx includes support for managing env vars and virtualenv for python using .rtx.toml.

If you find you continue to need direnv, please open an issue and let me know what it is to see if it's something rtx could support. rtx will never be as capable as direnv with a DSL like .envrc, but I think we can handle enough common use cases to make that unnecessary for most people.

rtx makes use of caching in many places in order to be efficient. The details about how long to keep cache for should eventually all be configurable. There may be gaps in the current behavior where things are hardcoded, but I'm happy to add more settings to cover whatever config is needed.

Below I explain the behavior it uses around caching. If you're seeing behavior where things don't appear to be updating, this is a good place to start.

Each plugin has a cache that's stored in ~/$RTX_CACHE_DIR/<PLUGIN>. It stores the list of versions available for that plugin (rtx ls-remote <PLUGIN>), the legacy filenames (see below), the list of aliases, the bin directories within each runtime installation, and the result of running exec-env after the runtime was installed.

Remote versions are updated daily by default or anytime that rtx ls-remote is called explicitly. The file is zlib messagepack, if you want to view it you can run the following (requires msgpack-cli).

cat ~/$RTX_CACHE_DIR/nodejs/remote_versions.msgpack.z | perl -e 'use Compress::Raw::Zlib;my $d=new Compress::Raw::Zlib::Inflate();my $o;undef $/;$d->inflate(<>,$o);print $o;' | msgpack-cli decode

Note that the caching of exec-env may be problematic if the script isn't simply exporting static values. The vast majority of exec-env scripts only export static values, but if you're working with a plugin that has a dynamic exec-env submit a ticket and we can try to figure out what to do.

Caching exec-env massively improved the performance of rtx since it requires calling bash every time rtx is initialized. Ideally, we can keep this behavior.