Does Run Once or similar exists?

[MCDesign]

Dear Forum,

Im making a Battle Royale Server with Gas borders that will shrink over time.

Now i made a Skript that enables On join. But i only want that the first person joins this command triggers.
Is this possible?

If that isn't possible, is it possible to skript that the command may not run more then once at a time?

Thanks for all the help in advance,

Newbie <---
[doublepost=1503139705,1503139669][/doublepost]This is the Skript sofar:

on join:
broadcast "Gas will move in 4 Minutes"
wait 4 minutes
execute console command "/shrink 500 3"
wait 3 minutes
broadcast "Gas will move in 4 Minutes"
wait 4 minutes
execute console command "/shrink 200 2"
wait 2 minutes
broadcast "Gas will move in 3 Minutes"
wait 3 minutes
execute console command "/shrink 100 1"
wait 1 minute
broadcast "Gas will move in 2 Minutes"
wait 2 minutes
execute console command "/shrink 50 1"
wait 1 minute
broadcast "Gas will move in 1 Minute"
wait 1 minute
execute console command "/shrink 25 1"

 

[Deleted member 5254]

dear. please use next time request help format. and code tags

and yes. there is a way. just set a variables...

on join:
    if {Bla} is not set:
         set {Bla} to true
         broadcast "GAS SINK"

 

[Deleted member 5254]

Or simply use the appropriate event

on first join: