diff --git a/man/systemctl.xml b/man/systemctl.xml
index 0ad0ad6d7e..78607c9ba3 100644
--- a/man/systemctl.xml
+++ b/man/systemctl.xml
@@ -1092,7 +1092,8 @@ kobject-uevent 1 systemd-udevd-kernel.socket systemd-udevd.service
enabled and disabled, or only enabled, or only disabled.
If the unit carries no install information, it will be silently ignored
- by this command.
+ by this command. NAME must be the real unit name,
+ any alias names are ignored silently.
For more information on the preset policy format, see
systemd.preset5.
diff --git a/man/systemd.preset.xml b/man/systemd.preset.xml
index b7164014f0..d09167baaf 100644
--- a/man/systemd.preset.xml
+++ b/man/systemd.preset.xml
@@ -98,6 +98,10 @@
Empty lines and lines whose first non-whitespace character is # or
; are ignored.
+ Presets must refer to the "real" unit file, and not to any aliases. See
+ systemd.unit5
+ for a description of unit aliasing.
+
Two different directives are understood:
enable may be used to enable units by default,
disable to disable units by default.
diff --git a/man/systemd.unit.xml b/man/systemd.unit.xml
index 85a7b12d76..f818e772a9 100644
--- a/man/systemd.unit.xml
+++ b/man/systemd.unit.xml
@@ -144,21 +144,31 @@
and are
equivalent.
- Time span values encoded in unit files can be written in
- various formats. A stand-alone number specifies a time in seconds.
- If suffixed with a time unit, the unit is honored. A concatenation
- of multiple values with units is supported, in which case the
- values are added up. Example: "50" refers to 50 seconds; "2min
- 200ms" refers to 2 minutes plus 200 milliseconds, i.e. 120200ms.
- The following time units are understood: s, min, h, d, w, ms, us.
- For details see
+ Time span values encoded in unit files can be written in various formats. A stand-alone number specifies a
+ time in seconds. If suffixed with a time unit, the unit is honored. A concatenation of multiple values with units
+ is supported, in which case the values are added up. Example: 50 refers to 50 seconds;
+ 2min 200ms refers to 2 minutes and 200 milliseconds, i.e. 120200 ms. The following time units
+ are understood: s, min, h, d,
+ w, ms, us. For details see
systemd.time7.
- Empty lines and lines starting with # or ; are
- ignored. This may be used for commenting. Lines ending
- in a backslash are concatenated with the following
- line while reading and the backslash is replaced by a
- space character. This may be used to wrap long lines.
+ Empty lines and lines starting with # or ; are ignored. This may be
+ used for commenting. Lines ending in a backslash are concatenated with the following line while reading and the
+ backslash is replaced by a space character. This may be used to wrap long lines.
+
+ Units can be aliased (have an alternative name), by creating a symlink from the new name to the existing name
+ in one of the unit search paths. For example, systemd-networkd.service has the alias
+ dbus-org.freedesktop.network1.service, created during installation as the symlink
+ /usr/lib/systemd/system/dbus-org.freedesktop.network1.service. In addition, unit files may
+ specify aliases through the Alias= directive in the [Install] section; those aliases are only
+ effective when the unit is enabled. When the unit is enabled, symlinks will be created for those names, and removed
+ when the unit is disabled. For example, reboot.target specifies
+ Alias=ctrl-alt-del.target, so when enabled it will be invoked whenever CTRL+ALT+DEL is
+ pressed. Alias names may be used in commands like enable, disable,
+ start, stop, status, …, and in unit dependency directives
+ Wants=, Requires=, Before=, After=, …,
+ with the limitation that aliases specified through Alias= are only effective when the unit is
+ enabled. Aliases cannot be used with the preset command.Along with a unit file foo.service, the
directory foo.service.wants/ may exist. All