/lib/systemd/system/hwclock -save.service
[root@hostname username]# more /lib/systemd/system/hwclock-save.service
[Unit]
Description=Synchronise Hardware Clock to System Clock
DefaultDependencies=no
Before=shutdown.target
ConditionFileIsExecutable=!/usr/sbin/ntpd
ConditionFileIsExecutable=!/usr/sbin/openntpd
ConditionFileIsExecutable=!/usr/sbin/chrony
ConditionVirtualization=!container
[Service]
Type=oneshot
ExecStart=/sbin/hwclock -D --systohc
[Install]
WantedBy=reboot.target halt.target poweroff.target
Таким образом, в конечном итоге он вызывает/sbin/hwclock