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
· 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 —
· A TTY agent that is temporarily spawned during systemctl(1)
· 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.
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.
The following options are understood:
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.
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:
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"
Specify the query timeout in seconds. Defaults to 90s. A timeout
of 0 waits indefinitely.
Echo the user input instead of masking it. This is useful when
using systemd-ask-password to query for usernames.
Never ask for password on current TTY even if one is available.
Always use agent system.
If passed, accept cached passwords, i.e. passwords previously
When used in conjunction with --accept-cached accept multiple
passwords. This will output one password per line.
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.
Print a short help text and exit.
This page is part of the systemd (systemd system and service manager)
project. Information about the project can be found at
⟨http://www.freedesktop.org/wiki/Software/systemd⟩. If you have a bug
report for this manual page, see
page was obtained from the project's upstream Git repository
⟨https://github.com/systemd/systemd.git⟩ on 2017-03-13. If you dis‐
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believe there is a better or more up-to-date source for the page, or
you have corrections or improvements to the information in this
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systemd 233 SYSTEMD-ASK-PASSWORD(1)