:into parameter accepts Collectable.t(), so you can use an empty list:

> System.shell("echo hello; sleep 1; echo world; sleep 1; echo end;", into: [])
{["hello\n", "world\n", "end\n"], 0}

or create a custom struct and implement Collectable protocol for it.

As far as I know, there’s no more higher-level abstractions in Elixir itself.

You have to:

• use Port directly
• or, some external packages, like porcelain

Personally, I prefer using Port directly, you can get more examples at:

• elixir - How to capture each line from System.cmd output? - Stack Overflow
• How to start an OS process in Elixir - Stack Overflow

I’m not sure about the context of your requirements. But personally, I always lean towards small and sufficient implementations rather than large and comprehensive ones. From that perspective, a simple Port wrapper is sufficient.