linux manpages
{"type":"documentation"}

SSH-ADD

Section: User Commands (1)
Index Return to Main Contents

BSD mandoc
 

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-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 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_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.
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-agent1, ssh-keygen1, 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.

 

Index

NAME
SYNOPSIS
DESCRIPTION
ENVIRONMENT
FILES
DIAGNOSTICS
SEE ALSO
AUTHORS
This document was created by man2html, using the manual pages.
Time: 05:29:11 GMT, December 24, 2015