Using the DOS Command-line

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The Working Directory

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When the DOS window first appears, it shows the name of the current, or working directory (folder). The name of the directory includes the drive letter, followed by a colon, followed by a backslash and a directory name, followed by a prompt symbol (>) like this:

it means that the current directory is the SYSTEM directory, which is a subdirectory of the WINDOWS directory stored on the C: drive. A series of directories like this, joined together using backslash characters, is known as a path. (This is just like the path used in a URL, except that URL paths follow the UNIX convention of a forward slash instead of a backslash.)

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Changing the Working Directory

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Here's another example. Suppose you want to move to the C:\WINDOWS\SYSTEM directory. You simply type the full path name of the desired destination:

For example, if you are in the C:\WINDOWS\SYSTEM directory typing this command will take you to the C:\WINDOWS directory. 

If you want to move to a subdirectory of your current directory (a child directory, in other words), you can just type the directory name, rather than the complete path. If you are in the C:\WINDOWS directory and you want to move to the C:\WINDOWS\SYSTEM directory. You can simply type 
 

rather than
 

In Windows, many folder names, such as "My Documents" and "Program Files" contain spaces, unlike the original version of DOS, where file and folder names were limited to eight characters and a three-character extension. To handle a pathname that contains spaces, put quotes around the name, like this:
 

To change from one drive to another, you don't use the cd command. Instead, you just type the name of the drive followed by a colon like this:

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Directory Listings

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There are some other parts of the directory listing that you might find of interest:

• The second column contains the word <DIR> if the entry is a subdirectory, and the size of the file in bytes if the entry is a regular file. 

 
• The first two entries, each of which is a subdirectory, have rather peculiar names. You can ignore these entries if you like: They refer to the current directory (.) and its parent directory (..). 

 
• The last two lines are a summary of the files in the directory. The of these shows that 18 files are listed (subdirectories and the two special entries are counted as files) and the files occupy a total of 49,057 bytes. The final line shows that over 1,843 MB of free space is available on the drive.

lists the contents of the C:\WINDOWS directory. If you attempt this, you'll find that there are too many lines to fit in the DOS window, and so the files will scroll off the top of the window. To prevent this, add the /p flag to the end of the dir command:
 

This causes the listing to stop each time the window fills up. You can read the listing and then press Enter to view the next page.

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Deleting, Copying, and Moving Files

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When using the command-line, deleted files are not placed in the "Recycle Bin", and there is no friendly prompt asking "Are you sure?": the file is instantly and silently deleted from your drive.

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WildCards

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In the same way, you can delete all the files in the current directory by simply typing
 

Obviously, this is very powerful, so be extra-careful when you use wildcards. If you accidentally type del *.java, when you meant to type del *.class, all of your .java files in the current directory will be erased; you will not be able to get them back.

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Copying Files

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Just like with del, you can use wildcards with the copy command. To copy all the HTML files the current directory to your A: drive, you would type
 

You can use the copy command to rename or move a file. To rename MyApplet.java to MyFirstApplet.java, you could type the following two commands:
 

This is relatively inefficient, however, since it takes time to copy all the bytes and there must be room on the drive for both the original file and the new file. A better approach is to use the ren command, which can also be written rename. For example, you could accomplish the same thing as the previous example by typing
 

Because the ren command doesn't actually move the bytes of the file, both the original file and the new file must be in the same  directory.

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Creating and Removing Directories

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The directory is created as a subdirectory of the current directory. If you like, you can create the directory as a subdirectory elsewhere by typing the full path name of the directory you want to create. For example, to create a directory named MyJavaFiles that is a subdirectory of C:\My Documents, you can type
 

Notice that we've used quotes around the directory name because the parent directory, (My Documents) has a space in it. In Windows 95 and 98, the parent directory must already exist. Windows NT and 2K will create the necessary parent directories.

To delete a directory, you use the rd command, which can also be written rmdir. The directory must be empty; that is, it must not contain any files or subdirectories. It must also not be the current working directory of any DOS window or running program. To delete a directory named C:\MUD, type
 

The directory is instantly and silently deleted. If you're in a hurry, you can delete a directory and all the files and subdirectories it contains by using the /s flag. Typing
 

will delete the C:\MUD directory and all it contains. But, DOS will politely ask you if you're sure before completing the irreversible deletion.

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Running Programs

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When the Edit program starts up, it will use the entire MS-DOS window like this:

When you start a Windows program from a DOS window, it does not run "inside" the DOS window, but launches it's own Window. To use Windows Notepad to create a C++ file called MyProgram.cpp, you'd simply type Notepad MyProgram.cpp and press ENTER like this: