ssh-add(1) - Linux man page
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
ssh-add -n [-T token]
-
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 toconfirmation before being used for authentication. Confirmationis performed by the SSH_ASKPASS program mentioned below.Successful confirmation is signaled by a zero exit status fromthe SSH_ASKPASS program, rather than text entered into therequester.
- -D' Deletes all identities from the agent.
-d' Instead of adding identities, removes identities from the agent. If ssh-add 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, ssh-add will append .pub and retry.
-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-T token
Explicitly set token name. 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.SSH_USE_STRONG_RNG
The reseeding of the OpenSSL random generator is usually done from /dev/urandom. If the SSH_USE_STRONG_RNG environment variable is set to value other than 0 the OpenSSL random generator is reseeded from /dev/random. The number of bytes read is defined by the SSH_USE_STRONG_RNG value. Minimum is 6 bytes. This setting is not recommended on the computers without the hardware random generator because insufficient entropy causes the connection to be blocked until enough entropy is available.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.
BSD April 14, 2013 BSD