calling python file

1. add this to the [RS274NGC] section of your ini file:
2. save your python script as eg 'M123' (possible numering is 100...199) to the 'mcodes' folder in your machine config directory and mark the file as executable

3.'M123' in Gcode should now execute the script.

 I did as you said but i get an error of unknown m code

Possible causes:
- USER_M_PATH is incorrect (this is supposed to point to the directory that contains your 'M199' file not to the file itself )
- File name is incorrect (Do not add an extension eg .py)
- The file is not marked as executable

 do i need to add REMAP = M199 python = M199(the name of the script)

No, this is not a remap, it's a custom mcode (which lets you use any executable script)