On Windows you can use something like that bat...

@echo off

echo:

set executable=zcashgpuclient_silentarmy.exe

set runforseconds=800
set restartinseconds=5
set /a counter=0
timeout 10
:start
start "zcashgpuclient" %executable%
echo:
echo The software will run for %runforseconds% seconds
timeout %runforseconds%
taskkill /f /im %executable%
echo:
echo Restarting the software in %restartinseconds% seconds (%counter%)
timeout %restartinseconds%
set /a counter+=1
echo:
echo:
goto start