Editing Windows Environment Variables

To install GEMPACK, you may be required to create or alter Windows Environment Variables, such as GPDIR or the PATH. The instructions below show how to do this for Windows 7 or later. For XP the procedure is very similar.

You will probably need Administrator rights to alter your Windows Environment Variables. Before you start, close any command prompt windows (DOS boxes) that are open. Also close other programs that are running, if they are not needed right now. Create a folder C:\TEMP, if that does not exist already.

Windows 7 or later: Follow steps 1 to 8 below.

Windows XP: Start by right-clicking on "My Computer" and select "Properties | Advanced | Environment Variables" and then follow steps 4 to 8 below.

	Step 1: Right-click on the "Computer" or "My Computer" desktop icon and select "Properties".
	Step 2: Choose advanced system settings.
	Step 3: Select the Advanced Tab and click the Environment Variables button. This should take you to the Environment Variables screen (pictured next).
	Step 4: To create a new Environment Variable click New (in either the USER or SYSTEM area). USER environment variable settings apply only to the current user. SYSTEM environment variable settings apply to all users of this PC. If USER and SYSTEM settings conflict (eg, you had two different settings for GPDIR) the USER setting dominates. However, the Windows PATH is made by appending the USER PATH variable to the SYSTEM PATH variable, so in this case the SYSTEM setting is dominant. The PATH variable is a list of folders, separated by semicolons (";"). When Windows looks for a program (eg, TABLO.EXE), it searches through these folders in order. For GEMPACK purposes we suggest that you create/edit USER settings such as: GPDIR=C:\GP TEMP=C:\TEMP TMP=C:\TEMP But for the PATH, edit the SYSTEM setting. Eg, you might add "C:\GP;" (don't forget the semicolon!) at the front of the SYSTEM PATH variable. To see your current environment settings (with merged USER and SYSTEM settings), open a command prompt window (DOS box) and type "SET". Or, type "SET >ENV.TXT" and examine the file ENV.TXT in a text editor.
	Step 5: In this example we set the new USER variable GPDIR to C:\GP. Press OK when done, to return to the Environment Variables screen.
	Step 6: To alter an existing Environment Variable, select it, then press Edit.
	Step 7: In this example we reset the USER variable TEMP to C:\TEMP. Press OK when done, to return to the Environment Variables screen.
	Step 8: To finish, click OK to get back to the System Properties Screen, then OK again to close that. If you have any command prompt windows (DOS boxes) open, close them. [DOS boxes that were opened before you edited Environment Variables will not reflect the new settings.]