Also this option should be added to usage:

# ssh-keygen -h
ssh-keygen: illegal option -- h
usage: ssh-keygen [options]
Options:
  -a trials   Number of trials for screening DH-GEX moduli.
  -B          Show bubblebabble digest of key file.
  -b bits     Number of bits in the key to create.
  -C comment  Provide new comment.
  -c          Change comment in private and public key files.
  -e          Convert OpenSSH to RFC 4716 key file.
  -F hostname Find hostname in known hosts file.
  -f filename Filename of the key file.
  -G file     Generate candidates for DH-GEX moduli.
  -g          Use generic DNS resource record format.
  -H          Hash names in known_hosts file.
  -i          Convert RFC 4716 to OpenSSH key file.
  -l          Show fingerprint of key file.
  -M memory   Amount of memory (MB) to use for generating DH-GEX moduli.
  -N phrase   Provide new passphrase.
  -P phrase   Provide old passphrase.
  -p          Change passphrase of private key file.
  -q          Quiet.
  -R hostname Remove host from known_hosts file.
  -r hostname Print DNS resource record.
  -S start    Start point (hex) for generating DH-GEX moduli.
  -T file     Screen candidates for DH-GEX moduli.
  -t type     Specify type of key to create.
  -v          Verbose.
  -W gen      Generator to use for generating DH-GEX moduli.
  -y          Read private key file and print public key.

NOTE:
As the function which prints usage is already available. Adding -h option would be very nice also

An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHBA-2011-0598.html