# Explanation of the Batch File

Here's some more explanation of the batch file used in the InstantTrack cURL tutorial.

 @echo off This turns off the echoing of each line in the command file as it executes. This is really optional, since the window where this is happening closes right away, without giving you much time to look at it, but it should reduce the amount of stuff that flashes by on the screen. c: cd \it These two commands set the default drive to the drive containing your InstantTrack directory, and the default path to that directory. Here I'm assuming that C:\IT is your InstantTrack directory. If we don't do this, the program will be run in some other directory, depending on how we start the batch file. InstantTrack might not be able to find its database files if run from someplace else. curl http://www.../nasa.all >nasa.all This command uses cURL to grab the latest elements from the Internet. It's then stored in the current directory (that's the InstantTrack directory) using the name nasa.all. It will overwrite any old version of nasa.all that may already be there, which is fine. it /f nasa.all This command runs InstantTrack in auto-update mode. The "/f" switch tells InstantTrack to treat the next argument as a filename and read it in as Keplerian elements (in Update mode).