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
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 environ‐
ment 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 confirma‐
tion before being used for authentication. Confirmation is
performed by ssh-askpass(1). Successful confirmation is sig‐
naled 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 inter‐
preted 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
Specifies the hash algorithm used when displaying key finger‐
prints. Valid options are: “md5” and “sha256”. The default is
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 repre‐
sented by the agent.
-l Lists fingerprints of all identities currently represented by
-q Be quiet after a successful operation.
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.
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 opera‐
tions on each.
Set a maximum lifetime when adding identities to an agent. The
lifetime may be specified in seconds or in a time format speci‐
fied 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.
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 call‐
ing 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.)
Identifies the path of a UNIX-domain socket used to communicate
with the agent.
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.
Contains the DSA, ECDSA, authenticator-hosted ECDSA, Ed25519,
authenticator-hosted Ed25519 or RSA authentication identity of
Identity files should not be readable by anyone but the user. Note
that ssh-add ignores identity files if they are accessible by others.
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.
This page is part of the openssh (Portable OpenSSH) project. Informa‐
tion about the project can be found at
http://www.openssh.com/portable.html. If you have a bug report for
this manual page, see ⟨http://www.openssh.com/report.html⟩. This page
was obtained from the tarball openssh-8.3p1.tar.gz fetched from
2020-06-09. If you discover any rendering problems in this HTML ver‐
sion of the page, or you believe there is a better or more up-to-date
source for the page, or you have corrections or improvements to the
information in this COLOPHON (which is not part of the original manual
page), send a mail to email@example.com
BSD February 7, 2020 BSD