Provided by: systemd_239-7ubuntu10_amd64 bug

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 use the system-wide query mechanism, which allows active users to respond
       via several agents, listed below.

       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(8),

       ·   A boot-time password agent querying the user directly on the console — systemd-ask-
           password-console.service(8),

       ·   An agent requesting password input via a wall(1) message — systemd-ask-password-
           wall.service(8),

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

       ·   A command line agent which can be started temporarily to process queued password
           requests — systemd-tty-ask-password-agent --query.

       Answering system-wide password queries is a privileged operation, hence all the agents
       listed above (except for the last one), run as privileged system services. The last one
       also needs elevated privileges, so should be run through sudo(8) or similar.

       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), systemd-ask-password-console.service(8), systemd-tty-ask-password-agent(1),
       keyctl(1), plymouth(8), wall(1)

NOTES

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

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