openssh/ssh-add.1

.\"	$OpenBSD: ssh-add.1,v 1.53 2010/08/31 11:54:45 djm Exp $
.\"
.\"  -*- nroff -*-
.\"
.\" Author: Tatu Ylonen <ylo@cs.hut.fi>
.\" Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
.\"                    All rights reserved
.\"
.\" As far as I am concerned, the code I have written for this software
.\" can be used freely for any purpose.  Any derived versions of this
.\" software must be clearly marked as such, and if the derived work is
.\" incompatible with the protocol description in the RFC file, it must be
.\" called by a name other than "ssh" or "Secure Shell".
.\"
.\"
.\" Copyright (c) 1999,2000 Markus Friedl.  All rights reserved.
.\" Copyright (c) 1999 Aaron Campbell.  All rights reserved.
.\" Copyright (c) 1999 Theo de Raadt.  All rights reserved.
.\"
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.\" modification, are permitted provided that the following conditions
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.Dd $Mdocdate: August 31 2010 $
.Dt SSH-ADD 1
.Os
.Sh NAME
.Nm ssh-add
.Nd adds private key identities to the authentication agent
.Sh SYNOPSIS
.Nm ssh-add
.Op Fl cDdLlXx
.Op Fl t Ar life
.Op Ar
.Nm ssh-add
.Fl s Ar pkcs11
.Nm ssh-add
.Fl e Ar pkcs11
.Sh DESCRIPTION
.Nm
adds private key identities to the authentication agent,
.Xr ssh-agent 1 .
When run without arguments, it adds the files
.Pa ~/.ssh/id_rsa ,
.Pa ~/.ssh/id_dsa ,
.Pa ~/.ssh/id_ecdsa
and
.Pa ~/.ssh/identity .
After loading a private key,
.Nm
will try to load corresponding certificate information from the
filename obtained by appending
.Pa -cert.pub
to the name of the private key file.
Alternative file names can be given on the command line.
.Pp
If any file requires a passphrase,
.Nm
asks for the passphrase from the user.
The passphrase is read from the user's tty.
.Nm
retries the last passphrase if multiple identity files are given.
.Pp
The authentication agent must be running and the
.Ev SSH_AUTH_SOCK
environment variable must contain the name of its socket for
.Nm
to work.
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl c
Indicates that added identities should be subject to confirmation before
being used for authentication.
Confirmation is performed by the
.Ev SSH_ASKPASS
program mentioned below.
Successful confirmation is signaled by a zero exit status from the
.Ev SSH_ASKPASS
program, rather than text entered into the requester.
.It Fl D
Deletes all identities from the agent.
.It Fl d
Instead of adding identities, removes identities from the agent.
If
.Nm
has been run without arguments, the keys for the default identities will
be removed.
Otherwise, the argument list will be interpreted as a list of paths to
public key files and matching keys will be removed from the agent.
If no public key is found at a given path,
.Nm
will append
.Pa .pub
and retry.
.It Fl e Ar pkcs11
Remove keys provided by the PKCS#11 shared library
.Ar pkcs11 .
.It Fl L
Lists public key parameters of all identities currently represented
by the agent.
.It Fl l
Lists fingerprints of all identities currently represented by the agent.
.It Fl s Ar pkcs11
Add keys provided by the PKCS#11 shared library
.Ar pkcs11 .
.It Fl t Ar life
Set a maximum lifetime when adding identities to an agent.
The lifetime may be specified in seconds or in a time format
specified in
.Xr sshd_config 5 .
.It Fl X
Unlock the agent.
.It Fl x
Lock the agent with a password.
.El
.Sh ENVIRONMENT
.Bl -tag -width Ds
.It Ev "DISPLAY" and "SSH_ASKPASS"
If
.Nm
needs a passphrase, it will read the passphrase from the current
terminal if it was run from a terminal.
If
.Nm
does not have a terminal associated with it but
.Ev DISPLAY
and
.Ev SSH_ASKPASS
are set, it will execute the program specified by
.Ev SSH_ASKPASS
and open an X11 window to read the passphrase.
This is particularly useful when calling
.Nm
from a
.Pa .xsession
or related script.
(Note that on some machines it
may be necessary to redirect the input from
.Pa /dev/null
to make this work.)
.It Ev SSH_AUTH_SOCK
Identifies the path of a
.Ux Ns -domain
socket used to communicate with the agent.
.El
.Sh FILES
.Bl -tag -width Ds
.It Pa ~/.ssh/identity
Contains the protocol version 1 RSA authentication identity of the user.
.It Pa ~/.ssh/id_dsa
Contains the protocol version 2 DSA authentication identity of the user.
.It Pa ~/.ssh/id_ecdsa
Contains the protocol version 2 ECDSA authentication identity of the user.
.It Pa ~/.ssh/id_rsa
Contains the protocol version 2 RSA authentication identity of the user.
.El
.Pp
Identity files should not be readable by anyone but the user.
Note that
.Nm
ignores identity files if they are accessible by others.
.Sh DIAGNOSTICS
Exit status is 0 on success, 1 if the specified command fails,
and 2 if
.Nm
is unable to contact the authentication agent.
.Sh SEE ALSO
.Xr ssh 1 ,
.Xr ssh-agent 1 ,
.Xr ssh-keygen 1 ,
.Xr sshd 8
.Sh AUTHORS
OpenSSH is a derivative of the original and free
ssh 1.2.12 release by Tatu Ylonen.
Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos,
Theo de Raadt and Dug Song
removed many bugs, re-added newer features and
created OpenSSH.
Markus Friedl contributed the support for SSH
protocol versions 1.5 and 2.0.