Personally, I use the way described
here more or less, and just add the script to the startup (remember to make it executable). The main program then exists while the forked copy continues as a daemon.
Otherwise, it should be enough to just add the script to your startup with a '&' afterwards to put it in the background, no need to have any shell script in between (as long as you have a correct shebang line, that is the #!/usr/bin/perl one in the start of your script. I think. :)
You have moved into a dark place.
It is pitch black. You are likely to be eaten by a grue.