[master] 5879216 Let process do -run as well

[Dridi Boukelmoune]

On Mon, Sep 12, 2016 at 10:14 PM, Guillaume Quintard
<guillaume at varnish-software.com> wrote:
> Any reason to not kill the shell command and just use process?

shell {...} vs process {...} -run (for the lazy dev)

Also err_shell.

I introduced the process command for background processes, maybe I
should've named it bgprocess.

Both have different purposes:

- `shell` commands for exit status checks
- `process` for background processes and automatic stdout/err capture