The bash shell is needed to run several shell scripts.
Bash (the GNU Bourne-Again SHell) is available for most UNIX and UNIX-like platforms. If it isn’t already installed or available as a package for your platform, you can get it at http://www.gnu.org/software/bash/bash.html.
After correct installation, typing at the bash command line prompt:
$ bash --version
should result in something like:
GNU bash, version 4.4.12(1)-release (x86_64-pc-linux-gnu) Copyright (C) 2016 Free Software Foundation, Inc.
Your version string will likely vary.