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Name

ssh-add - adds RSA or DSA identities to the authentication agent

Synopsis

ssh-add [-cDdLlXx] [-t life] [file ...]
ssh-add -s reader
ssh-add -e reader

Description

ssh-add 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, 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_config(5) .

-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.

See Also

ssh(1) , ssh-agent(1) , ssh-keygen(1) , sshd(8)

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.

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