systemd --version mirrors systemctl --version:
$ ./systemd --version
systemd 186
other
+PAM +LIBWRAP +AUDIT +SELINUX +IMA +SYSVINIT -LIBCRYPTSETUP
This information can be retrieved by other means (systemctl, etc.),
but it's easier for a newbie if 'systemd --version' says something
useful. And 'systemd --help' is already there, so let's complement
that with '--version'.
This adds a timeout if the TTY cannot be acquired and makes sure we
always output the question to the console, never to the TTY of the
respective service.
This option never made much sense. It was originally intended to make
sure that the usual startup output of sysv scripts goes to the terminal.
However, since SysV scripts started from a terminal would not output to
that terminal, but rather /dev/console this effect was more often than
not actually taking place. Nowadays systemd has much nicer boot time
status output than SysV which makes the sysv output redundant. Finally,
all output of services goes to the journal anyway, and is not lost.
Hence, let's drop this option, and simplify things a bit.
This also ensures that caps dropped from the bounding set are also
dropped from the inheritable set, to be extra-secure. Usually that should
change very little though as the inheritable set is empty for all our uses
anyway.
If systemd serializes from a switch_root, it adds "--switchedroot" to
the systemd in the real root.
If "--switchedroot" is found, then we do not skip all the stuff, which
is skipped for normal rexecs.
The ability to set MountAuto=no and SwapAuto=no was useful during the
adoption phase of systemd, so that distributions could stick to their
classic mount scripts a bit longer. It is about time to get rid of it
now.