Stories before: https://discuss.pytorch.org/t/failed-when-trying-to-install-pytorch-from-source/8603/15
And now, after some days’ costed by reinstalled Ubuntu (in fact, the computer itself have had to be repaired twice), I’m here trying to install it, using the docker.
Things seemed going well at first, but then failed at this command.

Step 10/14 : RUN git submodule update --init

It says,

fatal: Not a git repository (or any of the parent directories): .git
The command ‘/bin/sh -c git submodule update --init’ returned a non-zero code: 128

Mr. Google suggested me to run git init. Of course, it didn’t work.
Hope for a fast answer, since it has cost me REALLY a looooong time on it.
Thanks to everybody. I love you.