How to start another bash in Dockerfile

Question

I want to update GCC from 4.4.7 to 4.7.2 in a container(CentOS 6.9) following this tutorial How to upgrade GCC on CentOS.

In the end of the tutorial, the author uses <

Answer 1

Among the directives of the Dockerfile, you have SHELL

https://docs.docker.com/engine/reference/builder/#shell

from this doc

The SHELL instruction can also be used on Linux should an alternate shell be required such as zsh, csh, tcsh and others.