Adds private key identities to the authentication agent
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ssh-add adds private key identities to the
authentication agent, ssh-agent(1).
For RSA, ECDSA or DSA identity may contain X.509 certificate that
match private key. This certificate will be loaded as well. Also identity
may contain extra X.509 certificates. Agent client uses those 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_dsa. After loading a private key,
ssh-add will try to load corresponding custom
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,
asks for the passphrase from the user. The passphrase is read from the
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:
- 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 (X.509 or
custom) 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. If the argument list consists of “-” then
ssh-add will read public keys to be removed from
- Specifies the hash algorithm used when displaying key fingerprints. Valid
options are: “md5” and “sha256”. The default
- Remove keys provided by the PKCS#11 shared library
- When listing X.509 certificate based identities prints public key instead
certificate distinguished name.
When loading keys into or deleting keys from the agent,
process plain private keys only and skip custom certificates. In this
case it is ignored for X.509 certificate based identities.
- Lists public key parameters of all identities currently represented by the
agent. X.509 certificates are displayed with their “Distinguished
- Lists fingerprints of all identities currently represented by the
- Be quiet after a successful operation.
- 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.
-v options increase the verbosity. The
maximum is 3.
- Unlock the agent.
- Lock the agent with a password.
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
DISPLAY is 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
located in “libexec” directory. This is particularly useful
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.)
Remark: On Android
- Allows further control over the use of an askpass program. If this
variable is set to “never” then
ssh-add will never attempt to use one. If it is
set to “prefer”, then
prefer to use the askpass program instead of the TTY when requesting
passwords. Finally, if the variable is set to “force”, then
the askpass program will be used for all passphrase input regardless of
DISPLAY is set.
- Identifies the path of a UNIX-domain socket used
to communicate with the agent.
- Contains the DSA, ECDSA, Ed25519 or RSA authentication identity of the
For RSA, ECDSA or DSA identity file may contain X.509 certificate
that match private key and extra X.509 certificates.
Identity files should not be readable by anyone but the user. Note
Exit status is 0 on success, 1 if the specified command fails, and 2 if
ssh-add ignores identity files if they are
accessible by others.
ssh-add 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.