# general


11/12/2021, 1:59 AM
So, lets take
for example. You'd then ask for
./pants help-advanced
for that tool:
Copy code
$ ./pants help-advanced download-pex-bin

`download-pex-bin` subsystem options

The PEX (Python EXecutable) tool (<>).
Config section: [download-pex-bin]
None available.

`download-pex-bin` subsystem advanced options
      default: v2.1.54
      current value: v2.1.54
      Use this version of pex.
      Supported pex versions: >=2.1.51,<3.0

  --download-pex-bin-known-versions="['<str>', '<str>', ...]"
      default: [
      current value: [
      Known versions to verify downloads against.
      Each element is a pipe-separated string of `version|platform|sha256|length`, where:
        - `version` is the version string
        - `platform` is one of [linux_arm64,linux_x86_64,macos_arm64,macos_x86_64],
        - `sha256` is the 64-character hex representation of the expected sha256
          digest of the download file, as emitted by `shasum -a 256`
        - `length` is the expected length of the download file in bytes, as emitted by
          `wc -c`
      E.g., `3.1.2|macos_x86_64|6d0f18cd84b918c7b3edd0203e75569e0c7caecb1367bbbe409b44e28514f5be|42813`.
      Values are space-stripped, so pipes can be indented for readability if necessary.

      one of: [error, warning]
      default: error
      current value: error
      What action to take in case the requested version of pex is not supported.
      Supported pex versions: >=2.1.51,<3.0

      default: <{version}/pex>
      current value: <{version}/pex>
      URL to download the tool, either as a single binary file or a compressed file (e.g. zip file). You can change this to point to your own hosted file, e.g. to work with proxies or for access via the filesystem through a `file:$abspath` URL (e.g.
      `file:/this/is/absolute`, possibly by [templating the buildroot in a config file](<>.
      Use `{version}` to have the value from --version substituted, and `{platform}` to have a value from --url-platform-mapping substituted in, depending on the current platform. For example, <{version}-{platform}.zip>.

  --download-pex-bin-url-platform-mapping="{'key1': val1, 'key2': val2, ...}"
      default: {}
      current value: {}
      A dictionary mapping platforms to strings to be used when generating the URL to download the tool.
      In --url-template, anytime the `{platform}` string is used, Pants will determine the current platform, and substitute `{platform}` with the respective value from your dictionary.
      For example, if you define `{"macos_x86_64": "apple-darwin", "linux_x86_64": "unknown-linux"}, and run Pants on Linux with an intel architecture, then `{platform}` will be substituted in the --url-template option with unknown-linux.

`download-pex-bin` subsystem deprecated options
None available.
That gives you the details of which options to set.
🙌 2