systemd-ask-password(1)

NAME

   systemd-ask-password - Query the user for a system password

SYNOPSIS

   systemd-ask-password [OPTIONS...] [MESSAGE]

DESCRIPTION

   systemd-ask-password may be used to query a system password or
   passphrase from the user, using a question message specified on the
   command line. When run from a TTY it will query a password on the TTY
   and print it to standard output. When run with no TTY or with --no-tty
   it will query the password system-wide and allow active users to
   respond via several agents. The latter is only available to privileged
   processes.

   The purpose of this tool is to query system-wide passwords --- that is
   passwords not attached to a specific user account. Examples include:
   unlocking encrypted hard disks when they are plugged in or at boot,
   entering an SSL certificate passphrase for web and VPN servers.

   Existing agents are:

   *   A boot-time password agent asking the user for passwords using
       Plymouth

   *   A boot-time password agent querying the user directly on the
       console

   *   An agent requesting password input via a wall(1) message

   *   A command line agent which can be started temporarily to process
       queued password requests

   *   A TTY agent that is temporarily spawned during systemctl(1)
       invocations

   Additional password agents may be implemented according to the systemd
   Password Agent Specification[1].

   If a password is queried on a TTY, the user may press TAB to hide the
   asterisks normally shown for each character typed. Pressing Backspace
   as first key achieves the same effect.

OPTIONS

   The following options are understood:

   --icon=
       Specify an icon name alongside the password query, which may be
       used in all agents supporting graphical display. The icon name
       should follow the XDG Icon Naming Specification[2].

   --id=
       Specify an identifier for this password query. This identifier is
       freely choosable and allows recognition of queries by involved
       agents. It should include the subsystem doing the query and the
       specific object the query is done for. Example:
       "--id=cryptsetup:/dev/sda5".

   --keyname=
       Configure a kernel keyring key name to use as cache for the
       password. If set, then the tool will try to push any collected
       passwords into the kernel keyring of the root user, as a key of the
       specified name. If combined with --accept-cached, it will also try
       to retrieve such cached passwords from the key in the kernel
       keyring instead of querying the user right away. By using this
       option, the kernel keyring may be used as effective cache to avoid
       repeatedly asking users for passwords, if there are multiple
       objects that may be unlocked with the same password. The cached key
       will have a timeout of 2.5min set, after which it will be purged
       from the kernel keyring. Note that it is possible to cache multiple
       passwords under the same keyname, in which case they will be stored
       as NUL-separated list of passwords. Use keyctl(1) to access the
       cached key via the kernel keyring directly. Example:
       "--keyname=cryptsetup"

   --timeout=
       Specify the query timeout in seconds. Defaults to 90s. A timeout of
       0 waits indefinitely.

   --echo
       Echo the user input instead of masking it. This is useful when
       using systemd-ask-password to query for usernames.

   --no-tty
       Never ask for password on current TTY even if one is available.
       Always use agent system.

   --accept-cached
       If passed, accept cached passwords, i.e. passwords previously
       entered.

   --multiple
       When used in conjunction with --accept-cached accept multiple
       passwords. This will output one password per line.

   --no-output
       Do not print passwords to standard output. This is useful if you
       want to store a password in kernel keyring with --keyname but do
       not want it to show up on screen or in logs.

   -h, --help
       Print a short help text and exit.

EXIT STATUS

   On success, 0 is returned, a non-zero failure code otherwise.

SEE ALSO

   systemd(1), systemctl(1), keyctl(1), plymouth(8), wall(1)

NOTES

    1. systemd Password Agent Specification
       http://www.freedesktop.org/wiki/Software/systemd/PasswordAgents

    2. XDG Icon Naming Specification
       http://standards.freedesktop.org/icon-naming-spec/icon-naming-spec-latest.html

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