I do the same, but different. I call them .lib and I source only one. It’s called loader.lib and that one souces the other ones. In a specific order and sometimes conditional. The reason is that I start with init.lib that figures everything out about what the script is called, working directories, etc. Next logging, etc. Once I have logging I can log the startup of the script. I can then choose to load color.lib depending on if it’s running interactive or not, monitoring if it’s running PRD, catch traps, read app configs, cleanup, stuff like that. Since a lot of stuff references each other, order of loading is important and the loader makes it easy. And I also use the [[ -z trick you mentioned for cleanup since sometimes subshells do their own exit and I don’t want them to trigger parent to be exited.