End of Life Ruby 3.0 has reached end of life and gets no more fixes. Switch to Ruby 4.0 →

instance method

OptionParser#on

on(*params, &block)

# File tmp/rubies/ruby-3.0.5/lib/optparse.rb, line 1523
def on(*opts, &block)
  define(*opts, &block)
  self
end

Add option switch and handler. See make_switch for an explanation of parameters.

See also #notwice #on_head #new #on_tail also in 4.1 · 4.0 · 3.4 · 3.3 · 3.2 · 3.1