Configuration of asdf encompasses both the sharable .tool-versions files as well as user specific customisations with .asdfrc and Environment Variables.


Whenever .tool-versions file is present in a directory, the tool versions it declares will be used in that directory and any subdirectories.


Global defaults can be set in the file $HOME/.tool-versions

This is what a .tool-versions file looks like:

ruby 2.5.3
nodejs 10.15.0

You can also include comments:

ruby 2.5.3 # This is a comment
# This is another comment
nodejs 10.15.0

The versions can be in the following format:

  • 10.15.0 - an actual version. Plugins that support downloading binaries, will download binaries.
  • ref:v1.0.2-a or ref:39cb398vb39 - tag/commit/branch to download from github and compile
  • path:/src/elixir - a path to custom compiled version of a tool to use. For use by language developers and such.
  • system - this keyword causes asdf to passthrough to the version of the tool on the system that is not managed by asdf.


Multiple versions can be set by separating them with a space. For example, to use Python 3.7.2, fallback to Python 2.7.15 and finally to the system Python, the following line can be added to .tool-versions.

python 3.7.2 2.7.15 system

To install all the tools defined in a .tool-versions file run asdf install with no other arguments in the directory containing the .tool-versions file.

To install a single tool defined in a .tool-versions file run asdf install <name> in the directory containing the .tool-versions file. The tool will be installed at the version specified in the .tool-versions file.

Edit the file directly or use asdf local (or asdf global) which updates it.


Add an .asdfrc file to your home directory and asdf will use the settings specified in the file. The file below shows the required format with the default values to demonstrate:

legacy_version_file = no
use_release_candidates = no
always_keep_download = no
plugin_repository_last_check_duration = 60


Plugins with support can read the versions files used by other version managers, for example, .ruby-version in the case of Ruby's rbenv.

no defaultUse .tool-versions to read versions
yesUse plugin fallback to legacy version files (.ruby-version) if available


Configure the asdf update command to upgrade to the latest Release Candidate instead of the latest Semantic Version.

no defaultSemantic Version is used
yesRelease Candidate is used


Configure the asdf install command to keep or delete the source code or binary it downloads.

no defaultDelete source code or binary after successful install
yesKeep source code or binary after install


Configure the duration since the last asdf plugin repository sync to the next. Commands asdf plugin add <name> or asdf plugin list all will trigger a check of the duration, if the duration has passed then a sync occurs.

integer in range 1 to 999999999
60 is default
Sync on trigger event if duration since last sync has passed
0Sync on each trigger event
neverNever sync

Environment Variables

  • ASDF_CONFIG_FILE - Defaults to ~/.asdfrc as described above. Can be set to any location.
  • ASDF_DEFAULT_TOOL_VERSIONS_FILENAME - The filename of the file storing the tool names and versions. Defaults to .tool-versions. Can be any valid filename. Typically you should not override the default value unless you know you want asdf to ignore .tool-versions files.
  • ASDF_DIR - Defaults to ~/.asdf - Location of the asdf scripts. If you install asdf to some other directory, set this to that directory. For example, if you are installing via the AUR, you should set this to /opt/asdf-vm.
  • ASDF_DATA_DIR - Defaults to ~/.asdf - Location where asdf install plugins, shims and installs. Can be set to any location before sourcing or mentioned in the section above. For Elvish, this can be set above use asdf.

Internal Configuration

Users should not worry about this section as it describes configuration internal to asdf useful for Package Managers and integrators.

  • $ASDF_DIR/asdf_updates_disabled: Updates via the asdf update command are disabled when this file is present (content irrelevant). This is used by Package Managers like Pacman or Homebrew to ensure the correct update method is used for the particular installation.