systemctl help
linux
Show the manual pages for one or more units, or for the unit a process belongs to (by PID).
More info →Examples (5)
Show the manual page for a specific unit
systemctl help unitShow the manual pages for multiple units
systemctl help unit1 unit2 ...Show the manual page for a user unit
systemctl help unit --userShow the manual page without a pager (all at once)
systemctl help unit --no-pagerShow the manual page for the unit of a process by PID
systemctl help pidmade by @shridhargupta | data from tldr-pages