ssh-add(1) — Linux manual page


SSH-ADD(1)             BSD General Commands Manual            SSH-ADD(1)

NAME         top

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

SYNOPSIS         top

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

DESCRIPTION         top

     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 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

     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

     -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.  If the argument list consists
             of “-” then ssh-add will read public keys to be removed
             from standard input.

     -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

     -X      Unlock the agent.

     -x      Lock the agent with a password.

ENVIRONMENT         top

             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.

             SSH_ASKPASS_REQUIRE 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 ssh-add will 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 whether DISPLAY is set.

             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.

FILES         top

             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

EXIT STATUS         top

     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         top

     ssh(1), ssh-agent(1), ssh-askpass(1), ssh-keygen(1), sshd(8)

AUTHORS         top

     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.

COLOPHON         top

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BSD                           July 14, 2020                          BSD