Issue with Shell script with waitForOutput false & writing to file

April 21, 201411 yr

For debugging purposes, I'm trying to do a tcpdump on OS X for a "Send Mail" script step, and I'd like this to run on the user computers, logging just for the relevant timeframe.

The shell script I'm using is along the lines of:

tcpdump -c 100 > $HOME/test.txt

I was hoping to be able to use ScriptMaster to circumvent the sad limitation that FileMaker can only do one thing at a time.

If I launch tcpdump with a shell script inside an AppleScript, the next script step (Send Mail) will only execute after tcpdump has terminated.

If I use Run Shell Script ( command ; waitForOutput ; timeout ) with waitForOutput = true works fine, but obviously has the same limitation.

If I use Run Shell Script ( command ; waitForOutput ; timeout ) with waitForOutput = false, a file is created but for some reason nothing is written to it.

Does anybody have ideas on what I'm doing wrong, or possibly what other means I could use to achieve the same thing?