$ perl -E 'say $^O'
darwin

$ perl -v
This is perl 5, version 26, subversion 1 (v5.26.1) built for darwin-2level

$ uname -a
Darwin MYHOSTNAME 16.7.0 Darwin Kernel Version 16.7.0: Thu Jun 21 20:07:39 PDT 2018; root:xnu-3789.73.14~1/RELEASE_X86_64 x86_64