— Adds private key identities
to the authentication agent
adds private key identities to the authentication
. In addition identity may contain X.509
certificate that match private key. For RSA, ECDSA or DSA identity may contain
extra X.509 certificates. Agent uses extra certificates along with
certificates from system default X.509 store to build chain of certificates
leading to a trusted certificate authority. When run without arguments, it
adds the files ~/.ssh/id_rsa
. After loading a private key,
will try to load corresponding certificate
information from the filename obtained by appending
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.
retries the last passphrase if multiple identity
files are given.
The authentication agent must be running and the
environment variable must contain the
name of its socket for ssh-add
The options are as follows:
- 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.
- Deletes all identities from the agent.
- 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
- Specifies the hash algorithm used when displaying key
fingerprints. Valid options are: “md5” and
“sha256”. The default is “sha256”.
- Remove keys provided by the PKCS#11 shared library
- When loading keys into or deleting keys from the agent,
process plain private keys only and skip certificates.
- Lists public key parameters of all identities currently
represented by the agent. X.509 certificates are displayed with their
- Lists fingerprints of all identities currently represented
by the agent.
- Be quiet after a successful operation.
- File with extra X.509 certificates in PEM format
concatenated together. Certificates are added to X.509 store and together
with those from system default store are used in public key algorithms in
RFC 6187 format if applicable. Note that currently only EC keys support
- Add keys provided by the PKCS#11 shared library
- Tests whether the private keys that correspond to the
specified pubkey files are usable by performing sign
and verify operations on each.
- Set a maximum lifetime when adding identities to an agent.
The lifetime may be specified in seconds or in a time format specified in
- 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.
- Unlock the agent.
- Lock the agent with a password.
- 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
SSH_ASKPASS are set, it will execute the program
SSH_ASKPASS that may open a X11
window to read the passphrase. Note if
is not set will be executed program ssh-askpass located
in “libexec” directory. 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
- Identifies the path of a
UNIX-domain socket used to communicate with the
- Contains the DSA authentication identity of the user.
- Contains the ECDSA authentication identity of the
- Contains the Ed25519 authentication identity of the
- Contains the RSA authentication identity of the user.
For RSA, ECDSA or DSA identity file may contain X.509 certificate that match it.
In addition file may contain extra X.509 certificates. Extra certificates
along with certificates from X.509 store are used to build chain of
certificates leading to a trusted certificate authority if required by public
key algorithm format.
Identity files should not be readable by anyone but the user. Note that
ignores identity files if they are accessible by
Exit status is 0 on success, 1 if the specified command fails, and 2 if
is unable to contact the authentication agent.
PKIX-SSH 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.
Roumen Petrov contributed support for X.509 certificates.