T happens to be written in Ruby but it's a CLI, not a Ruby library. The fact that it is packaged as a gem is incidental. T was designed to be called from a command line shell and to interoperate with other Unix utilities like grep, cut, awk, bc, wc, xargs, etc. All output is streamed to stdout, so it actually makes just as much sense to call t from a shell script (or, for that matter, from a Perl or Python script) as it does from Ruby.