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$Mdocdate: February 7 2020 $

openssh-client

secure shell (SSH) client, for secure access to remote machines

openssh

Premier connectivity tool for remote login with the SSH protocol

openssh-clients

An open source SSH client applications

NAME

ssh-add - adds private key identities to the OpenSSH authentication agent

SYNOPSIS

ssh-add [-cDdKkLlqvXx] [-E fingerprint_hash] [-S provider] [-t life] [] ssh-add -s pkcs11 ssh-add -e pkcs11 ssh-add -T pubkey ...

DESCRIPTION

ssh-add adds private key identities to the authentication agent, ssh-agent(1). When run without arguments, it adds the files ~/.ssh/id_rsa, ~/.ssh/id_dsa, ~/.ssh/id_ecdsa, ~/.ssh/id_ecdsa_sk, ~/.ssh/id_ed25519, and ~/.ssh/id_ed25519_sk. After loading a private key, ssh-add will try to load corresponding certificate information from the filename obtained by appending -cert.pub to the name of the private key file. 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 ssh-askpass(1). Successful confirmation is signaled by a zero exit status from ssh-askpass(1), 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 and their corresponding certificates will be removed. Otherwise, the argument list will be interpreted as a list of paths to public key files to specify keys and certificates to be removed from the agent. If no public key is found at a given path, ssh-add will append .pub and retry.
-E fingerprint_hash
Specifies the hash algorithm used when displaying key fingerprints. Valid options are: "md5" and "sha256". The default is "sha256".
-e pkcs11
Remove keys provided by the PKCS#11 shared library pkcs11.
-K Load resident keys from a FIDO authenticator.
-k When loading keys into or deleting keys from the agent, process plain private keys only and skip certificates.
-L Lists public key parameters of all identities currently represented by the agent.
-l Lists fingerprints of all identities currently represented by the agent.
-q Be quiet after a successful operation.
-S provider
Specifies a path to a library that will be used when adding FIDO authenticator-hosted keys, overriding the default of using the internal USB HID support.
-s pkcs11
Add keys provided by the PKCS#11 shared library pkcs11.
-T pubkey ...
Tests whether the private keys that correspond to the specified pubkey files are usable by performing sign and verify operations on each.
-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).
-v Verbose mode. Causes ssh-add to print debugging messages about its progress. This is helpful in debugging problems. Multiple -v options increase the verbosity. The maximum is 3.
-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 (by default "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 Ns -domain socket used to communicate with the agent.
SSH_SK_PROVIDER
Specifies a path to a library that will be used when loading any FIDO authenticator-hosted keys, overriding the default of using the built-in USB HID support.

FILES

~/.ssh/id_dsa
~/.ssh/id_ecdsa
~/.ssh/id_ecdsa_sk
~/.ssh/id_ed25519
~/.ssh/id_ed25519_sk
~/.ssh/id_rsa
Contains the DSA, ECDSA, authenticator-hosted ECDSA, Ed25519, authenticator-hosted Ed25519 or 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.

EXIT STATUS

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

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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