I want to build a docker image from ubuntu image. It is required to change the default sh from dash to bash manually. (Because it require to install many rpm packages which contains bash scripts)
dpkg-reconfigure dash
Is there any method to let this action automatically without human behavior?
In my Dockerfile it maybe written as(Method 1)
RUN dpkg-reconfigure dash
I've tried another method(Method 2)
RUN ln -sf bash /bin/sh
But, both method can not work.
Pasting Daniel's comment as an answer here since it doesn't rely on default settings from dpkg-reconfigure.
To get options:
debconf-show dash
To set this particular option to false:
echo "dash dash/sh boolean false" | debconf-set-selections
and to actually reconfigure the package:
DEBIAN_FRONTEND=noninteractive dpkg-reconfigure dash
This worked for me from a Dockerfile:
# make /bin/sh symlink to bash instead of dash:
RUN echo "dash dash/sh boolean false" | debconf-set-selections
RUN DEBIAN_FRONTEND=noninteractive dpkg-reconfigure dash
You can make debconf only ask for high or critical questions[1].
Ex:
dpkg-reconfigure -p critical dash
dpkg-reconfigure will use default answer defined in debconf script. You can also use debconf-get-selections to pick up different answer for noninteractive installation[2].
Through some trial & error and much assistance from others, this ansible statement does the same thing:
# See "/var/cache/debconf/config.dat" for name of config item after changing manually
- name: aws-ssm ansible plugin fails if dash is the default shell
ansible.builtin.debconf:
name: dash/sh
question: dash/sh
value: false
vtype: boolean
You should instead patch those scripts to use #!/bin/bash instead of #!/bin/sh. Newer versions of Debian and Ubuntu no longer support using anything other than dash for /bin/sh.
debconf-show dashto get options.echo "dash dash/sh boolean false" | debconf-set-selectionsandDEBIAN_FRONTEND=noninteractive dpkg-reconfigure dashto do non-interactive configuring. – Daniel YC Lin Feb 12 '14 at 11:38