ssh-agent [-c | -s] [-d] [command [args ...]]
     ssh-agent [-c | -s] -k

DESCRIPTION
     ssh-agent is a program to hold private keys used for  public
key authentiM--
     cation (RSA, DSA).  The idea is that ssh-agent is started in
the beginM--
     ning of an X-session or a login session, and all other  win-
dows or proM--
     grams  are  started  as  clients  to  the ssh-agent program.
Through use of
     environment variables the agent can be located and automati-
cally used for
     authentication  when  logging  in  to  other  machines using
ssh(1).

     The options are as follows:

     -c      Generate C-shell commands on stdout.   This  is  the
default if
             SHELL looks like it's a csh style of shell.

     -s       Generate  Bourne shell commands on stdout.  This is
the default if
             SHELL does not look like it's a csh style of  shell.

     -k       Kill  the current agent (given by the SSH_AGENT_PID
environment
             variable).

     -d      Debug mode.  When this option is specified ssh-agent
will not
             fork.

     If  a commandline is given, this is executed as a subprocess
of the agent.
     When the command dies, so does the agent.

     The agent initially does not have any  private  keys.   Keys
are added using
     ssh-add(1).   When  executed  without  arguments, ssh-add(1)
adds the files
     $HOME/.ssh/id_rsa, $HOME/.ssh/id_dsa and  $HOME/.ssh/identi-
ty.  If the
     identity   has   a   passphrase,  ssh-add(1)  asks  for  the
passphrase (using a
     small X11 application if running under X11, or from the ter-
minal if runM--
     ning  without  X).  It then sends the identity to the agent.
Several idenM--
     tities can be stored in the agent; the agent  can  automati-

in the netM--
     work in a secure way.

     There  are  two  main ways to get an agent setup: Either the
agent starts a
     new subcommand into which some environment variables are ex-
ported, or the
     agent  prints  the  needed  shell  commands (either sh(1) or
csh(1) syntax can
     be generated) which can be evalled  in  the  calling  shell.
Later ssh(1)
     looks  at  these variables and uses them to establish a con-
nection to the
     agent.

     The agent will never send a private  key  over  its  request
channel.
     Instead,  operations that require a private key will be per-
formed by the
     agent, and the result will be  returned  to  the  requester.
This way, priM--
     vate keys are not exposed to clients using the agent.

     A     unix-domain     socket     is    created    (/tmp/ssh-
XXXXXXXX/agent.<pid>), and the
     name of this socket is stored in the SSH_AUTH_SOCK  environ-
ment variable.
     The  socket  is  made  accessible  only to the current user.
This method is
     easily abused by root or another instance of the same  user.

     The  SSH_AGENT_PID  environment  variable  holds the agent's
PID.

     The agent exits automatically when the command given on  the
command line
     terminates.

FILES
     $HOME/.ssh/identity
             Contains  the  protocol version 1 RSA authentication
identity of
             the user.

     $HOME/.ssh/id_dsa
             Contains the protocol version 2  DSA  authentication
identity of
             the user.

     $HOME/.ssh/id_rsa
             Contains  the  protocol version 2 RSA authentication
identity of
     Tatu Ylonen.  Aaron Campbell, Bob Beck, Markus Friedl, Niels
Provos, Theo
     de Raadt and Dug Song removed many bugs, re-added newer fea-
tures and creM--
     ated OpenSSH.  Markus Friedl contributed the support for SSH
protocol
     versions 1.5 and 2.0.

SEE ALSO
     ssh(1), ssh-add(1), ssh-keygen(1), sshd(8)

BSD                                 September       25,      1999
BSD