Question: In Windows, how can I display the startup items from using a batch file?

Answer: 
Your startup items are a combination of your own items and the "All Users" items. You can find your own with:

```
dir "%homedrive%%homepath%\start menu\progams\startup"

```

and the "All Users" ones (usually) with:

```
dir "%homedrive%%homepath%\..\all users\start menu\progams\startup"

```

All you have to do is manipulate the file names to remove the path and the ".lnk" at the end to get the shortcut names.

If you `cd` to those directories first and just do dir, you won't even have to remove the path.

**UPDATE:**

If, as your comments seem to indicate, you want all things that start when your system starts, they're found all over the place. You'll want to get a copy of [Autoruns](http://technet.microsoft.com/en-us/sysinternals/bb963902.aspx) (or its command-line brother, Autorunsc, for your purposes).

This is the best approach since it's "blessed" by Microsoft themselves.
As already answered, the startup items are a combination of startup items for "All Users" and the current user. The startup items can either be placed as links in the Start Menu Startup folders, or as registry entries.

For the startup folders, you have already been given the paths in Pax' answer, but do be aware that the paths will be different in non-english versions of Windows. 

For the registry, I don't think you can query it using batch script only. It can be done from PowerShell script, if that is an option. Otherwise, I think the easiest way to accomplish the task would be to make a small utility program for the task. (It would be easy to do in one of the .NET languages, or you can do it in C if you cannot rely on the .NET Framework being present).

The Registry entries can be found here, for All Users:

```
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

```

And for the current user:

```
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run

```

Finally, be aware that the registry also contains the RunOnce key; which contains entries that only should be run once at startup, and then be removed.