[TxMt] "Run Command" question -- also echo text in TM?

[David Wooten]

Greetings,
I'm trying to figure out a clever little trigger mechanism for Running 
a Command sort of "invisibly". I'd like to assign a certain command to 
the comma "," key, for example, and yet have the comma appear in the 
current TM window, thus running the said command whenever I happen in 
the natural course of events to type a comma ;). Now the closest I've 
come is to "echo" the comma and send the results to the current window, 
but of course this also gives me the output from the command which I 
wish to be discarded.
Any takers?
Thanks again,
David