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.Either way you end up seeing the Display Properties screen shown in Figure 3.2.As you can see, Microsoft took two main approaches with this release ofWindows.If you know exactly where you want to go, you can use the more tra-ditional Control Panel approach.If you want to carry out a task but don t knowhow to get there, you can use the more task-orientated approach.Alternatively, you could have reached the same screen via the desktop byright-clicking anywhere on the desktop and selecting Properties, and againwww.syngress.com 189_XP_03.qxd 11/9/01 2:29 PM Page 95Exploring the Windows XP User Interface " Chapter 3 95selecting the Settings tab, or you could have achieved the same result via thecommand line.To get to the Display Properties screen via the command line,click Start | Command Prompt to bring up a command window and typecontrol desk.cpl, as shown in Figure 3.3.Figure 3.2 Display PropertiesFigure 3.3 Command Line for Accessing Control Panel AppletsThere isn t really any reason, however, for the average user to use the com-mand line to carry out any of the tasks that they require.www.syngress.com 189_XP_03.qxd 11/9/01 2:29 PM Page 9696 Chapter 3 " Exploring the Windows XP User InterfaceFrom an administrator s perspective, it is always useful to know what tricksusers can employ to circumvent any restrictions that you may have put in place.Let me give you a real-life example.At one of the companies I did some consul-tancy for, the Control Panel had been rendered unavailable by use of the SystemPolicies.However, some clever users had obviously been doing some reading upand were using the command line to invoke the desk.cpl file to allow them totake off the standard background and disable the standard screen-saver settings tolockout their workstation.It was amazing at how fast this knowledge was trans-ferred around the company.The point I m trying to make here is that there arevarious methods that you can employ to prevent this type of action such astighter permission control, and so on.Remember though, you can t preventsomething that you don t know about.You can find all of the cpl files listed in Table 3.1 in the %systemroot%\system32 directory.If you haven t come across %systemroot% before, it is an envi-ronmental variable.In the majority of cases, your %systemroot% directory will bec:\winnt.Table 3.1 Control Panel Applet FilenamesControl Panel Applet CPL FileAccessibility Wizard Access.cplAdd/Remove Programs Appwiz.cplDisplay Desk.cplInternet Settings Inetcpl.cplRegional & Language Options Intl.cplGaming Options Joy.cplMouse Main.cplSounds & Audio Options Mmsys.cplNetwork Connections Ncpa.cplAdministrative Tools\Data Sources (ODBC) Odbc32.cplPower Options Powercfg.cplSystem Sysdm.cplPhone & Modem Options Telephon.cplDate & Time Timedate.cplwww.syngress.com 189_XP_03.qxd 11/9/01 2:29 PM Page 97Exploring the Windows XP User Interface " Chapter 3 97Configuring & Implementing&Environment VariablesIf you come from a programming background, you will already be quitefamiliar with variables.For those of you who aren t familiar with them,a variable is a placeholder for a value that is held in memory.Environment variables are similar except that they operate only withinthe environmental concerns of the operating system.An example of thisis the path variable which stores a list of directories on your computer.For example, if you were in a command window and typed a programname, it will use the path variable as a search path by looking for theprogram in each of the individual directories specified in that variable.The advantage of using environment variables is that because they arestored in memory, they are very fast.Windows has three different types of environment variables:System environment variables, created for the operatingsystemUser environment variablesThose that have been specified in an autoexec.bat statementYou can view the environment variables that are available on thesystem by either clicking the Environment Variables button in theControl Panel system applet or by typing the command set from a com-mand window.In the day-to-day use of Windows, you may not have to worrymuch about them, but it is useful to know that they exist and howthey work.You can also create your own via the Control Panel or againvia the command line; this can be especially useful for scriptingpurposes, for example, if you need to hold a value temporarily
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