optionally close terminal after execution

[v4hn]

With terminal: true the terminal always executes a bash shell after the real command to keep the terminal open and be able to inspect the output.
But for some longer-running scripts it is very useful to be able to ctrl+c them from the command line, although there is no reason to keep them open.

We could only keep the terminal open when the script returns an error exit code (|| bash instead of ; bash), but then we might loose log output displays when the error does not result in a non-zero exit code.

It probably makes more sense to invent a different flag like close_on_exit.