Adding pre-link, post-link, and pre-unlink scripts#

You can add scripts to a recipe. They must be located in the same directory as the meta.yaml file. The following scripts can be added:

  • pre-link---Executed before the package is installed. An error is indicated by a nonzero exit and causes conda to stop and causes the installation to fail.

  • post-link---Executed after the package is installed. An error is indicated by a nonzero exist and causes installation to fail. If there is an error, conda does not write any package metadata.

  • pre-unlink---Executed before the package is removed. An error is indicated by a nonzero exist and causes the removal to fail.

In addition to being co-located with the meta.yaml file, they must be named simply or post-link.bat. Conda-build will rename them to .<name>-<action>.sh (or .bat) where <name> is the package name and <action> is one of the preceeding actions.

These scripts are executed in a subprocess by conda, using %COMSPEC% /c <script> on Windows and /bin/bash <script> on macOS and Linux.

The convention for the path and filenames of these scripts on Windows is:


On Linux and macOS the convention is:


The scripts set the following environment variables:


The install prefix.


The name of the package.


The version of the package.


The build number of the package.

The scripts are:

  • Windows:

    • pre-link.bat

    • post-link.bat

    • pre-unlink.bat

  • macOS and Linux:




Post-link and pre-unlink scripts should:

  • Be avoided whenever possible.

  • Not touch anything other than the files being installed.

  • Not write anything to stdout or stderr, unless an error occurs.

  • Not depend on any installed or to-be-installed conda packages.

  • Depend only on simple system tools such as rm, cp, mv, and ln.

The scripts should not write to stdout or stderr unless an error occurs, but they may write to $PREFIX/.messages.txt, which is shown after conda completes all actions.