Recently I got really interested in debloating and hardening my operating systems, cause I’m heavily inspired by Unix and “worse is better” philosophy. As I heard bash is heavy and we have much more lightweight and faster alternatives like these mentioned in title. They must be great alternative for scripting and interpreting but is there any reason to use them on my machines as interactive shell? Anyone are using them? Also is it worth to learn them as bash is standard IT industry?
I was asking about that ksh because I love OpenBSD and in OpenBSD it’s default shell. As I like to experiment with different operating systems, not only Linux I think that much better for me would be to learn POSIX shell. What’s difference between POSIX shell and bash by the way?
POSIX shell is the standard that all shells should support (Fish does not I think). Its basically what is executed if you run it as
/usr/bin/shscript. POSIX is not a specific shell itself, its just the standard./usr/bin/shis usually a symbolic link to an actual shell interpreter. And any shell could support it, in example Bash with its compatibility mode (what is usually done by default in todays Linux systems). Or Dash is designed to do that specifically and only that as far as I know.Bash on the other hand is an enhanced shell that introduces some concepts, features and changes default behavior of the standard POSIX. That is when the script runs with
/usr/bin/bash. This is also used in your terminal as the interactive shell. And ZSH in example is similar to Bash, but has some extended features over Bash. They are relatively speaking similar. I think ZSH is or was the default shell in MacOS too.As for KSH, I don’t have no experience about this myself. I only know it exists and just saw checklists of differences.
ZSH is used by MacOS at the moment as interactive shell. I have these shitty laptops in school