Field Mapping for the Merge Tool Using Command Line

i'm creating a simple script to run in the command line of arcgis and one of the tasks i need to execute is a Merge. I'm merging three feature classes that have slightly different fields so i need to include field mapping within the command. i can't seem to find any examples of the syntax for field mapping i would use to add it to my command. does anyone have any examples? or know where i can find some examples? i've been looking on the ESRI support site and the internet for awhile now with no luck.

any help would be much appreciated.

thank you for your time.

adam