ssh-add
adds RSA or DSA identities to the authentication agent,
ssh-agent1.
When run without arguments, it adds the files
~/.ssh/id_rsa
~/.ssh/id_dsa
and
~/.ssh/identity
Alternative file names can be given on the command line.
If any file requires a passphrase,
ssh-add
asks for the passphrase from the user.
The passphrase is read from the user's tty.
ssh-add
retries the last passphrase if multiple identity files are given.
The authentication agent must be running and the
SSH_AUTH_SOCK
environment variable must contain the name of its socket for
ssh-add
to work.
The options are as follows:
-c
Indicates that added identities should be subject to confirmation before
being used for authentication.
Confirmation is performed by the
SSH_ASKPASS
program mentioned below.
Successful confirmation is signaled by a zero exit status from the
SSH_ASKPASS
program, rather than text entered into the requester.
-D
Deletes all identities from the agent.
-d
Instead of adding the identity, removes the identity from the agent.
-e reader
Remove key in smartcard
reader
-L
Lists public key parameters of all identities currently represented
by the agent.
-l
Lists fingerprints of all identities currently represented by the agent.
-s reader
Add key in smartcard
reader
-t 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
sshd_config5.
-X
Unlock the agent.
-x
Lock the agent with a password.
ENVIRONMENT
DISPLAY and SSH_ASKPASS
If
ssh-add
needs a passphrase, it will read the passphrase from the current
terminal if it was run from a terminal.
If
ssh-add
does not have a terminal associated with it but
DISPLAY
and
SSH_ASKPASS
are set, it will execute the program specified by
SSH_ASKPASS
and open an X11 window to read the passphrase.
This is particularly useful when calling
ssh-add
from a
.xsession
or related script.
(Note that on some machines it
may be necessary to redirect the input from
/dev/null
to make this work.)
SSH_AUTH_SOCK
Identifies the path of a unix-domain socket used to communicate with the
agent.
FILES
~/.ssh/identity
Contains the protocol version 1 RSA authentication identity of the user.
~/.ssh/id_dsa
Contains the protocol version 2 DSA authentication identity of the user.
~/.ssh/id_rsa
Contains the protocol version 2 RSA authentication identity of the user.
Identity files should not be readable by anyone but the user.
Note that
ssh-add
ignores identity files if they are accessible by others.
DIAGNOSTICS
Exit status is 0 on success, 1 if the specified command fails,
and 2 if
ssh-add
is unable to contact the authentication agent.
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.
