Class: SFL

 "2.3".freeze
 %r([\*\?\{\}\[\]<>\(\)~&\|\\\$;'`"\n])m.freeze
 {       :in  => STDIN,       :out => STDOUT,       :err => STDERR,     }

 argument
 command
 environment
 option

SFL.new(‘ls’, ’-a’) becomes

  @environment = {}
  @command = ['ls', 'ls']
  @argument = ['-a']
  @option = {}