anchor.diff:  
   *-Nkey*:: use the nth YubiKey found.
   
  -*−1*:: change the first configuration. This is the default and is
  +*-1*:: change the first configuration. This is the default and is
   normally used for true OTP generation. In this configuration, the option
   flag *-oappend-cr* is set by default.
   
  -*−2*:: change the second configuration. This is for YubiKey II only
  +*-2*:: change the second configuration. This is for YubiKey II only
   and is then normally used for static key generation. In this
   configuration, the option flags **-oappend-cr**, **-ostatic-ticket**,
   **-ostrong-pw1**, *-ostrong-pw2* and *-oman-update* are set by default.
   
   *-z*:: delete configuration in selected slot
   
  -*−s*'file':: save configuration to file instead of key. (if file
  +*-s*'file':: save configuration to file instead of key. (if file
   is -, send to stdout)
   
  -*−i*'file':: read configuration from file. (if file is -, read
  +*-i*'file':: read configuration from file. (if file is -, read
   from stdin) Configuration import is only valid for the ycfg format.
   
  -*−f*'format':: format to be used with *-s* and *-i*. Valid options are *ycfg* and *legacy*.
  -
  -*−a*['xxx']:: the AES secret key as a 32 (or 40 for OATH-HOTP/HMAC CHAL-RESP) char hex value (not modhex) (none to prompt for key on stdin) If *−a* is not used a random key will be generated.
  -
  -*−c*'xxx':: A 12 char hex value (not modhex) to use as access
  +*-f*'format':: format to be used with *-s* and *-i*. Valid options are *ycfg* and *legacy*.
  +
  +*-a*['xxx']:: the AES secret key as a 32 (or 40 for OATH-HOTP/HMAC CHAL-RESP) char hex value (not modhex) (none to prompt for key on stdin) If *-a* is not used a random key will be generated.
  +
  +*-c*'xxx':: A 12 char hex value (not modhex) to use as access
   code for programming. NOTE: this does NOT SET the access code, that’s
   done with **-oaccess**__=__.
   
  -*−o*'option':: change configuration option. Possible option arguments are:
  +*-o*'option':: change configuration option. Possible option arguments are:
   
   *fixed*='fffffffffff'::: The modhex _public identity_ of the YubiKey, 0-32 characters long
   (encoding up to 16 bytes). It’s possible to give the identity in hex as
  
positive.code: ~~~~~~~~~~~~~~
  
  When using OATH-HOTP mode, a HMAC key of 160 bits (20 bytes, 40 chars of
  hex) can be supplied with *−a*.
  
  
  Challenge-response Mode
  
negative.code: details.
  
  === YubiKey 2.3 firmware and above
  [-]*use-numeric-keypad*::
  
  Send scancodes for numeric keypad keypresses when sending digits - helps
  with some keyboard layouts. This option is only valid for the 2.x
  firmware line.
  
  [-]*fast-trig*::
  
  Faster triggering when only configuration 1 is available. This option is
  always in effect on firmware versions 3.0 and above.
  
  [-]*allow-update*::
  
  Allow updating (or swapping) of certain parameters in a configuration at
  a later time.
  
  [-]*dormant*::
  
  Hides/unhides a configuration stored in a YubiKey.
  
  
  === YubiKey 2.4/3.1 firmware and above
  [-]*led-inv*::
  
  Inverts the behaviour of the led on the YubiKey.
  
  