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One common use of DOS batch files is to copy multiple files from one disk or sub‐directory to another. For example, you may have a batch file called BACKUP.BAT that looks somewhat like this and copies all files in the current subdirectory with a TXT or DOC extension to drive B:

You've probably heard of the ASCII code, but do you know what it is? ASCII (pronounced ask‐ee) is an acronym for American Standard Code for Information Interchange. It's a standard way of assigning unique numbers to each alphanumeric character and punctuation mark used in the English language. For example, a capital A is assigned 65 as its ASCII code. Standard coding ensures that any machine using the ASCII code will display a capital A in response to a code 65. Of course, there are other, incompatible coding schemes to accomplish the same thing (ask an IBM mainframe user about EBCDIC— another acronym, pronounced eb‐suh‐dick), but in the micro world, ASCII reigns supreme.

If you're creating a batch file that you expect to be around for a while, especially if it does anything complex, it's a good idea to scatter remarks throughout the file to inform other people (and yourself) how the file works. To put a remark in a batch file, simply start a line with REM followed by a space. DOS will recognize the line as a remark and will not attempt to process it. If there is an ECHO OFF command earlier in the batch file, the remarks won't be displayed as they are encountered; otherwise they're displayed but not acted on.

Even if you're a new user of MS‐DOS microcomputers, you've probably seen a key marked Num Lock somewhere on your keyboard. Num Lock (for Numeric Lock) causes the dual‐purpose numeric keypad on the right side of most MS‐DOS keyboards to generate numbers (when Num Lock is ON) or to control cursor or other screen movement (when Num Lock is OFF). Certain MS‐DOS computers always boot up with Num Lock set to ON. This is probably the way you want it set if you do lots of numeric data input, but many microcomputer programs use the cursor control keys (Left and Right Arrows, Home, End, etc.) for everything from menu selection to viewing documents. To run these programs, you probably want Num Lock to be OFF. Sure, lots of keyboards (including the standard M310 Workstation keyboard) repeat the cursor control keys elsewhere on the keyboard, but some users (including myself) are very familiar with the placement and “feel” of the cursor control keys that are shared with the numeric keypad.

Here's a little tidbit I came up with the hard way a few weeks ago. I was backing up my hard disk, making a neat pile of diskettes as the BACKUP program filled them with data. I decided to label them (♯1, ♯2, etc.) after the BACKUP process was complete. Suddenly, an imaginary mouse skittered across my desk, followed by my very real, bounding cat. Disks flew everywhere! Once the dust settled, I realized I had a problem. Which disks were which?

You may have had the experience of typing a document in which a specific word or phrase, perhaps a company or library name, occurs repeatedly in the text. To save yourself the trouble of frequent retyping, simply enter a code such as “@1” everywhere the repeating word or phrase occurs. Then, when the whole document is entered, use your word processor's “Find and Replace” function to replace “@1” with the actual text. You can have several of these “macros” in one document by using codes “@2”, “@3”, etc. (Watch out if you get to “@10”. A “@1” is hiding in there!)

Like many regular PC users, I've developed a number of small batch files that automate various DOS processes. Many of these have appeared in this space over the years, but for the benefit of new readers I'd like to bring them all together. DOS‐tips veterans will find a few new ones in here, too—so let's get to 'em!

One of the most important aspects of programming in BASIC or any other language involves the interaction between the program and its user. For a typical microcomputer, the principal channels for this interaction are via the CRT screen and the keyboard. (Mouse‐based systems such as the Macintosh constitute a separate universe, requiring a fundamentally different approach to programming.) This article focuses on user‐to‐program interaction via the keyboard in BASIC programs. This keyboard interaction may involve user‐issued commands, menu selections, data entry—anything the user “tells” the program. The programming techniques are similar in all cases. Here, we'll look at a specific technique for getting a menu selection from the user.

In the last issue, we explored several techniques for transmitting printer control commands from an IBM PC/XT or M300 Workstation to the system printer. These commands are simply sequences of characters that turn special print modes—compressed, emphasized, etc.,—on and off. Recently, an additional technique, which works on Epson, IBM, and Epson‐compatible dot matrix printers, has come to light. If you have some other type of printer, you may also want to try it to see what happens.

Here's a trick that lets you use Smartcom II to communicate directly with your modem. I could hardly believe it! Press <F1> to get to the on‐line screen, then type ATZ and press <CTRL> <6> (that is, press the two keys simultaneously). Use the 6 key in the top row, not the numeric keypad. The modem will return an OK response. From that point on, you can use the full “AT” command set to set special registers, modes of operation, etc. Check your modem manual to see what commands the modem can respond to.