commander pitfalls, try coffee ./test.coffee --flag1 false

gistfile1.js

#!/usr/bin/env node

program = require 'commander'

program
  .option('--flag1 [true/false]', 'Flag1 (default = false)', false)
  .option('--flag2 [true/false]', 'Flag2 (default = false)', ((val) -> (val is "true")), false)
  .parse process.argv

# value is a string if given
if program.flag1
  console.log "flag1(#{typeof program.flag1}) is true"
else
  console.log "flag1(#{typeof program.flag1}) is false"

# value is converted to a boolean
if program.flag2
  console.log "flag2(#{typeof program.flag2}) is true"
else
  console.log "flag2(#{typeof program.flag2}) is false"