Allow stdin redirection (somehow?)

[nature40]

Allow stdin redirection (somehow?)

[gh0st42]

RUN bash -c 'echo -e "bushberry\nbushberry" | passwd pi' works fine

[gh0st42]

The errors just don't appear...
bash -c doesn't work at all.

RUN apt-get -y dist-upgrade executes.
RUN /bin/bash -c "apt-get -y dist-upgrade" doesn't:

apt 1.4.8 (armhf)
Usage: apt-get [options] command
       apt-get [options] install|remove pkg1 [pkg2 ...]
       apt-get [options] source pkg1 [pkg2 ...]

apt-get is a command line interface for retrieval of packages
and information about them from authenticated sources and
for installation, upgrade and removal of packages together
with their dependencies.
[..]

[oxzi]

I will take a look at this soon.

A hacky workaround would be creating an install script, INSTALLing it, RUN it and RUN rm it afterwards.