getopts が最新の 1.6/1.7 で動かなくなっているようなので、
取り急ぎ報告します。

knu@archon[2]% ruby -v -r getopts -e 'getopts("a:")'
ruby 1.6.7 (2002-03-01) [i386-freebsd5]
/usr/local/lib/ruby/1.6/getopts.rb:119:in `getopts': (eval):1:in `getopts': compile error (SyntaxError)
(eval):1: parse error
$OPT_: = val
      ^
	from /usr/local/lib/ruby/1.6/getopts.rb:118:in `eval'
	from /usr/local/lib/ruby/1.6/getopts.rb:119:in `getopts'
	from /usr/local/lib/ruby/1.6/getopts.rb:118:in `each'
	from /usr/local/lib/ruby/1.6/getopts.rb:118:in `getopts'
	from -e:1
=> {1}
knu@archon[2]% ruby17 -v -r getopts -e 'getopts("a:")'
ruby 1.7.2 (2002-03-01) [i386-freebsd5]
(eval):1:in `getopts': compile error
(eval):1: parse error
$OPT_: = val
      ^: (eval):1:in `getopts': compile error (SyntaxError)
(eval):1: parse error
$OPT_: = val
      ^
	from /usr/local/lib/ruby/1.7/getopts.rb:118:in `eval'
	from /usr/local/lib/ruby/1.7/getopts.rb:119:in `getopts'
	from /usr/local/lib/ruby/1.7/getopts.rb:118:in `each'
	from /usr/local/lib/ruby/1.7/getopts.rb:118:in `getopts'
	from -e:1
=> {1}

-- 
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Akinori MUSHA aka / (_ /  ( (__(  @ iDaemons.org / and.or.jp

"Somewhere out of a memory.. of lighted streets on quiet nights.."