Linux

https://www.nushell.sh/ ?? sort of PowerShell without Microsoft?

It's certainly capable, and has a more structured pipeline structure saving you in theory from awkwardness of grep/awk sorts of 'processing' that may be out of whack. It also has a command model where whether you are calling cmdlets or .Net functions, it's lighter weight than a typical bash interaciton that has to fork/exec every little thing (and the ability to invoke .Net functions means a lot of capabilities that are normally not directly available to something like bash).

However, from a user experience, it's got a few things that can be a problem:

• It's a bit too 'programmer-y', and particularly maybe a bit too perl-y. Some of the same criticisms of how perl can be a bit of a mess carry over to powershell.
• It's ecosystem is mostly just whatever Microsoft gives to you. The *nix side of the house has had a diverse ecosystem, but Microsoft is largely on their own. Good hooks into most Microsoft products, but not a whole not of third party enablement.
• Other shells have better and/or richer UX, like fish