In kernel-programming we should avoid doing call_usermodehelper() which allows to execute a command from kernel-space. And sometimes we even want to call this function within a systemcall. Normally, we really don't wanna do this. But, desperate times require extraordinary methods.
When I first tried to execute call_usermodehelper() within a systemcall() I got a kernel failure. So I googled and what I found was:
GNU parallel is an amazing command line tool for executing jobs in parallel using one or more machines. It has a lot of features and therefore a lot of options. Fortunately the manual page is full of examples.
My plan was to control some power outlets(16 ampere) using any browser(for example with a mobile phone). I wanted to use electronics only and tried to avoid relays.
➜ ~ ruby -e 'puts %w[t o m].permutation.map &:join' tom tmo otm omt mto mot