MySh

This is a basic shell, written to prove that shell is not that complex as a definition he told :)

Using this as your default shell

It is safe to use this as your default shell, because you still will be able to start a different shell, such as zsh by typing zsh, or run a executable at any location by typing the full path. So anytime, you can start zsh, bash, or run chsh to change default shell

Compile

gcc -o mysh mysh.c

Probably copy mysh to somewhere like /usr/local/bin/

Add entry to /etc/shells

Considering the mysh binary is in /usr/local/bin/mysh, add it to /etc/shells, for eg. my /etc/shells now is like this:

/bin/sh
/bin/bash
/usr/bin/sh
/usr/bin/bash
/usr/bin/zsh
/bin/zsh
/usr/bin/tmux
/bin/tmux
/bin/ksh
/bin/rksh
/usr/bin/ksh
/usr/bin/rksh
/usr/local/bin/mysh

Change default shell

chsh -s /usr/local/bin/mysh $USER   # Change for current user, replace $USER
with whatever username you want to change the shell for

adi-g15/mysh

MySh

Using this as your default shell