Some people are of the opinion that the command line works one way. You type in a command and hope that you got all of the information right and received the correct result, which you then have to interpret. This entire activity sounds quite difficult, somewhat boring, and error prone to say the least. You have to wonder why someone would put themselves through all that pain.
However, the command line isn’t anything like the scenario just mentioned. Actually, if you know a few simple rules, using the command line doesn’t have to be hard at all. The following sections describe some of the methods you can use to work at the command line.
Using Utilities Directly
Generally, you’ll being using the command line by working with the utilities directly. After all, it’s a little hard to create a batch file or script if you don’t know how the command works. However, using a command doesn’t have to be hard. All you need to remember is two simple characters, /? . That command line switch says, “Help me!” The command usually will help by presenting you with some options for using it.
To open a command line, select the Start » Programs » Accessories » Command Prompt command. You’ll see a command prompt. Whenever you open a command prompt using this method, it opens in your home directory on the hard drive. Type TaskList /? and press Enter. Figure below shows what you’ll see. (I’ve scrolled back to the top so you can see the major entries.)
The first piece of information is the usage instructions for the command. A set of square brackets (  ) tells you about an optional input. In this case, everything is optional; you can use TaskList by itself. A slash ( / ) tells you about a command line switch. Sometimes command line switches appear with a dash ( - ) instead.
In either case, a command line switch configures the command to perform a task in a specific way. For example, TaskList doesn’t normally display services, but you can tell it to display services by adding the /SVC command line switch. Some command line switches depend on other command line switches. You’ll see the command line switches nested within multiple layers of square brackets in this situation.
For example, if you want to supply a password for logging into a remote system to view the tasks running on it, you must also supply the /System and /Username command line switches. In other cases, command line switches are mutually exclusive. The command line will separate these switches with the pipe ( | ) symbol.
The TaskList command won’t allow you to use the /M command line switch with the / SVC switch; you must select one or the other. After the usage information, you’ll normally see a description section for newer commands. The description tells you what task the command performs and why you would want to use it.
Sometimes this information is quite complete, as it is with the TaskList command, and in other cases, you’ll still be scratching your head after you read the description. Older commands don’t provide a description at all; you just have to know what task they perform, which is why many people don’t use them. A description of the individual parameters (or arguments and inputs) comes next.
These entries tell you how to use the individual command line switches. You’ll also discover about other kinds of information you must provide. For example, the Dir (directory) command information shown in Figure 1.4 tells you that you can provide a drive letter, followed by a colon, followed by a directory path, and ending with a filename specification. None of these entries is a command line switch, but they’re all important parameters.
The final section is a list of examples. Only a few commands provide this kind of information, but it’s always helpful when they do. The examples come in many forms. The T askList command provides a list of filters first, so you can see how to get the output you want. It provides actual usage examples next so you can see what to type at the command line.
The point is that most people could use a command at the command prompt if they simply knew the simple /? command line switch. Go ahead and try it out now with the TaskList and Dir commands. You’ll want to keep the /? command line switch in mind as you read about other commands in this book. Try it out with every one of them and you’ll find that most commands provide some information, usually enough to jog your memory when you need to use it .
Scripts are the next step up in complexity. A script uses a simple programming language to accomplish tasks. You can’t create complex applications using a script. For example, you wouldn’t want to write a word processor using a script. However, scripting languages provide more intelligence than a batch file can. In addition, you can access some of the functionality that Windows provides.
Consequently, rather than rely on utilities for every action, you can ask Windows for some help in automating your tasks. A script requires a special environment to run. Windows provides this environment in the form of a script interpreter. The interpreter reads every line of code you write in your script and performs the task it requests.
Writing scripts is a little harder than writing batch files, but not nearly as difficult as writing an application with a full-fledged programming language. Consequently scripts are exactly what many people need to automate tasks when they don’t want to learn a full-fledged programming language, yet find batch files less robust than they’d like.
Most of the tasks you perform using scripts have standard requirements and needs to execute successfully. Active Directory, the Windows enterprise database, requires some special handling to work correctly.
No matter how you work with the command line, whether you use individual commands, batch files, or scripts, you can schedule a task to run at a specific time. For example, if you want to defragment your hard drive every night, you can schedule the Defrag command to run automatically.
Of course, you’d better be certain that everything is set up correctly before you assume the computer can perform the task on its own. Many people begin using the Task Scheduler to run tasks that they could forget during normal work hours and then progress to after-hours tasks.
Relying on Third Party Utilities
The fact that Microsoft doesn’t spend much time advertising the command line should tell you something. The tools that Microsoft provides for working at the command line are basic, simple, and not always the best tools at your disposal. Third party tools for working at the command prompt have been around for a long time. Most of these products are mature, fully tested, and quite capable of making your command line experience everything it should be.