How to install dtrx with pip?

[Chris Angelico]

On Sun, Apr 26, 2015 at 10:50 AM, Peng Yu <pengyu.ut at gmail.com> wrote:
> I get the following error when I try to install pip. Does anybody know
> what it is wrong and how to fix it? Thanks.
>
> ~/Downloads$ pip install dtrx
> Downloading/unpacking dtrx
>   Could not find any downloads that satisfy the requirement dtrx
>   Some externally hosted files were ignored (use --allow-external dtrx
> to allow).
> Cleaning up...
> No distributions at all found for dtrx
> Storing debug log for failure in /Users/py/.pip/pip.log
> ~/Downloads$ pip install --allow-external dtrx
> You must give at least one requirement to install (see "pip help install")

This is a nasty peculiarity of pip's command-line arguments, which is
(I think) improved in newer versions of pip. The --allow-external
option stipulates that the one next package may be installed
externally, and that package might be a dependency of the one you're
actually asking for. For what you want to do, try this:

$ pip install --allow-external dtrx dtrx

which means "Pip, go and install (possibly getting an external package
for dtrx) dtrx. Thanks."

ChrisA