Here's the standard technique I usually use:
#!/usr/bin/env ruby
def usage(s)
$stderr.puts(s)
$stderr.puts("Usage: #{File.basename($0)}: [-l <logfile] [-q] file ...")
exit(2)
end
$quiet = false
$logfile = nil
loop { case ARGV[0]
when '-q': then ARGV.shift; $quiet = true
when '-l': then ARGV.shift; $logfile = ARGV.shift
when /^-/: then usage("Unknown option: #{ARGV[0].inspect}")
else break
end; }
# Program carries on here.
puts("quiet: #{$quiet} logfile: #{$logfile.inspect} args: #{ARGV.inspect}")