How to see what a console command does in GMod
Type help sbox_maxprops in the console to see that setting's help text, current value and flags, including whether it needs sv_cheats.
help
Shows the help text, value and flags of one command or setting.
help <name> Examples
help sbox_maxprops Show details for the prop limit.
Arguments
nameRequired- Command or setting name.
What it does
A quick way to check what a setting does and whether it needs sv_cheats.
The game's own description: Find help about a convar/concommand.
Run it on your server
On a SLASHPLAY server, type it in the Console tab of the server page; the reply shows right under it. A value set there lasts until the server restarts. To keep it, add the line to garrysmod/cfg/server.cfg. New to this? Start a GMod server first.
Your own
GMod server.
From $0.03 an hour, only while it runs. New accounts get 6 free tokens.