So what can you do with the source? Well, this is what GNU/Linux and Debian is all about. Even if you aren't an experienced developer, you can do things that can personalize your computing experience. Note that people all over the world create Debian whether as translators, documenters, developers, testers, bug-fixers, etc., etc. As both a fun example, and a functional example, we modify the BASH shell to show you what is involved, how relatively easy it is, and to show off that maybe a user-abusive interface is more in line with how computers should interact with us humans.

This walks through steps to modify bash (shell) on a Debian 10.10.0 / amd64 install.

To watch step-by-step on the LinuxCollections.com How To Video, see Debian Developer Collection on USB

This shows off how to configure/modify/install modified source for use on your system. This is not a disciplined approach for patches or serious development, more of a quick way to have some fun.

Example shows off how to build a more "user-abusive" command prompt…

Example starts with a full install with KDE Desktop and the Debian USB Developer Collection (LinuxCollections.com #51010)

[ ] = comments that cover relevant steps for full example (but not detailed)
( ) = comments about previous command, or options

[Install Debian 10.10.0 with KDE desktop]
[Insert Debian USB Developer Collection, and mount USB_Boot partition]
[Get to root Shell/Terminal/Command prompt (Konsole/use root password entered during install)]
#cd /media/user/USB_Boot/boot/mountusb
(change to mounted folder so you can run mountusb shell script)
#./mountusb.sh
(This mounts all ISO as sources, and updates /etc/apt/sources.list to reference ALL packages on all 30 DVDs)
#cd
(change to home directory as a working folder)
#apt-get -y install build-essential fakeroot devscripts
(default Yes answer, and install necessary packages to allow building)
#apt-get source bash
(Installs bash source, any error has to do with "loosely handling" code, safe to ignore for this example)
(if desired, install preferred editor, e.g. apt-get install vim (or use nano))
#cd bash-5.0
(change directory to installed source)
#vim execute_cmd.c
(search for "command not found" and modify to your desired error, e.g. "Get it right, Dipbrain!", then save the file)
#apt-get -y build-dep bash
(make sure any build dependencies required by bash are installed, default Yes to install)
#debuild -b -uc -us
(debuild is a front end to build debian packages, uses dkpg-buildpackage, etc. ("man debuild" for more details), the -b is a binary build, -uc unsigned changes, do not sign modifications/changes, -us unsigned source, do not sign source package (example is for fun/personal use))
#cd ..
(up one folder where newly built .deb package is located)
#PATH=$PATH:/sbin
(add /sbin to root path for ldconfig/install tools)
#dpkg -i bash_5.0-4_amd64.deb
(debian package install with our newly build .deb package)

Now run a new terminal window (so new bash process is created, i.e. the bash we just built), and type a bad command…

You too can create a user abusive operating system that tells it like it is…

For other details and examples, see wiki entry: Debian Building Tutorial