Hello and welcome to our forums,
If you'd like to create a really lightweight setup package (that displays only a few dialogs, or even a single one), please have a look over the following FAQ:
How do I create a lightweight setup with a single dialog?
Regarding your first request:
I want to make an installer that basically:
Silently install other programs
Run a shell script
Clone a git repo
1.
Silently install other programs
This should be possible through our predefined support for prerequisites. If the programs you want to install have a silent switch (command), then this will be fairly easy.
Add prerequisites
2.
Run a shell script
If by "shell" script you refer to PowerShell, then you can achieve this through our predefined custom actions:
Run Inline PowerShell script
3.
Clone a git repo
I am not quite familiar with this, but I do not see why this wouldn't be achievable.
Hope it helps!
Best regards,
Catalin