That is part of an IDE feature list.
An IDE is never going to be as flexible as a unix environment. It can deliver some of that, but it's likely you will run into limitations sooner or later.
From the point of view from Xerox PARC workstation experience, which is kind of replicated in modern IDEs, it is the UNIX experience that fails short.
The shell is a subset of what an IDE REPL is capable of, with OS API integration and structured data manipulation.
As for background processes, that is a basic feature of any modern IDE.
It's very limiting not to have a shell, and arbitrary execution environment, and the wealth of tools which have been created over the years for the *nix environment.