REGEX Troubles... Can't find any examples

Action68

Hi,
I am trying to use replacements function of Repetier, to be able to use the Linear advance function of Marlin's Fixed Time Motion.
I have say: "M900 K0.00005" I need it to change to "M493 K0.00005".
https://regex101.com/  is not of much help as according to it I dont have to write anything but it will still copy the number to the replacement..
So I need just the M900 part replaced with M493.

Can anyone help?

Repetier

^M900 K(\d.?\d*)
would match it and @1 holds the number of K part as it is in first group ()

Action68

Thank You. Will try it out :
Regular Expression: ^M900 K(\d.?\d*) for
G-Code to execute: M493 K@1