After all the research, I am still highly inclined towards Golang. Since you said "Perl or Go", you seem to have used Golang. How does Perl compare with it?
UNIX commandline and Perl is a match made in heaven.
Using Golang will demand significantly more effort when doing more complex stuff but will give you concurrency, easier deploys/multi-platform support and better performance if doing CPU intensive stuff.
Thanks to the quick compile time and good tooling Go almost feels like a scripting language when developing but especially for UNIXy stuff it can't replace Perl for me.
Beginning Perl by Ovid.
Modern Perl by chromatic.