Rocker creates Raspberry Pi images with Dockerfile like syntax.
Rockerfile defines the image:
# Use the latest raspbian as base
FROM raspbian:latest
# Set some Network config
RUN set_static_ip.sh eth0 192.168.0.10
# Add input from somewhere
ADD my_custom_prog.tar /home/user/my_custom_prog/
ADD my_custom_prog2.tar /home/user/my_custom_prog/
Build image from current folder
rocker build <output image> .
Flash image
rocker flash <image file> [<device>]
if <device> is omitted, user is prompted with currently available storage devices ordered by detection time (visible) with newest first.