Hey! These docs are for version 2.12, which is no longer officially supported. Click here for the latest version, 2.18!

To run an executable/script, use `./pants run` on a [`pex_binary`](🔗) target. (See [package](🔗) for more on the `pex_binary` target.)


To pass arguments to the script/executable, use `--` at the end of the command, like this:

You may only run one target at a time.

The program will have access to the same environment used by the parent `./pants` process, so you can set environment variables in the external environment, e.g. `FOO=bar ./pants run project/app.py`. (Pants will auto-set some values like `$PATH`).

Tip: check the return code

Pants will propagate the return code from the underlying executable. Run `echo $?` after the Pants run to see the return code.

Issues finding files?

Run `./pants dependencies --transitive path/to/binary.py` to ensure that all the files you need are showing up, including for any [assets](🔗) you intend to use.

## Watching the filesystem

If the app that you are running is long lived and safe to restart (including web apps like Django and Flask or other types of servers/services), you can set `restartable=True` on your `pex_binary` target to indicate this to Pants. The `run` goal will then automatically restart the app when its input files change!

On the other hand, if your app is short lived (like a script) and you'd like to re-run it when files change but never interrupt an ongoing run, consider using `./pants --loop run` instead. See [Goals](🔗) for more information on `--loop`.

## Debugging

Tip: Using the IntelliJ/PyCharm remote debugger

First, add the following target in some BUILD file (e.g., the one containing your other 3rd-party dependencies):

You can check this into your repo, for convenience.

Now, use the remote debugger as usual:

  1. Start a Python remote debugging session in PyCharm, say on port 5000.

  2. Add the following code at the point where you want execution to pause and connect to the debugger:

Run your executable with `./pants run` as usual.

Note: The first time you do so you may see some extra dependency resolution work, as `pydevd-pycharm` has now been added to the binary's dependencies, via inference. If you have dependency inference turned off in your repo, you will have to manually add a temporary explicit dependency in your binary target on the `pydevd-pycharm` target.