adds RSA or DSA identities to the authentication agent, ssh-agent(1) . 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, asks for the passphrase from the user. The passphrase is read from the user's tty. 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 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_config(5) .

-X

Unlock the agent.

-x

Lock the agent with a password.

DISPLAY and SSH_ASKPASS

If needs a passphrase, it will read the passphrase from the current terminal if it was run from a terminal. If 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 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.

~/.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 ignores identity files if they are accessible by others.

Exit status is 0 on success, 1 if the specified command fails, and 2 if 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.