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---------------------------------------------------------------- INTERMEDIATE DOS COMMANDS ---------------------------------------------------------------- Life gets more interesting the longer you stay in the game. The more you want to accomplish with a computer, the more you need additional DOS commands. However, let's take a side trip to the keyboard and study several powerful DOS shortcuts. The keyboard function keys labelled F1 through F10 access a special buffer storage area of DOS. Additional key combinations offer other shortcuts. Some keyboards have twelve function keys while others have the function keys arranged along the top of the keyboard rather than stacked along the side. The best way to understand how the function keys work is to pause and explain the concept of a keyboard buffer which is little more than a temporary storage area in the computer's memory. A buffer is necessary because the activities of input and output (using the keyboard or printer) are much slower than those activities which interact with the speedy RAM memory chips and CPU. Data from the keyboard is placed into a memory buffer area until you signal the PC that you are ready to move on to the next task. Usually this signal is the carriage return or enter key. A buffer storage area can vary in size. For the DOS command line buffer, up to 127 characters can be contained. When data is entered into the keyboard buffer is stays there until flushed out. DOS allows some limited repeating and editing of data stored in the buffer (data you previously typed at the keyboard) by use of the function keys. The FUNCTION Keyboard: The following discussion applies to the function keys WHEN YOU ARE USING DOS! When you use an application such as your word processor or database program the function keys will probably have different uses! The function keys assume different roles for different programs. F1 through F5 have special meaning within DOS. They help in reissuing/editing the last DOS command typed. F1 Repeats one character per keystroke of the previous DOS command typed. F2 Repeats characters stored in the buffer up to the character you typed after pressing F2. F3 Repeats the entire LAST command. USEFUL! Repeat last command and edit it over again with other function keys or the backspace key. F4 Deletes all characters in the buffer up to the character you typed after F4. The buffer is not displayed. To see the buffer on screen tap F3. F5 Stores the current line for re-editing. F5 is used with the other four keys so you can repair long DOS commands which weren't typed in properly. When you press F5 the current line will be marked and the cursor will move down one line WITHOUT a new prompt. Then use the other function keys to finish editing. The main Keyboard Delete key deletes character on or to the right of the cursor Backspace key removes last character typed - to the left of cursor Insert key puts keyboard into insert mode Escape key voids current input and exits or escapes to previous settings PageUp key in many applications moves you up one screen of text PageDown key in many applications moves you down one screen of text Left and right arrow keys move cursor left and right without deleting Numlock key toggles (goes back and forth) between numbers on the numeric keypad and cursor control (functions such as page down, move cursor right, etc) Pressing two or more keys at the same time produces further results. You may hold down the Control (Ctrl) key and then press another key for a required result. Here are some two key combinations. Hold down the first key, then press the second: Shift-PrtSc prints one screen of data on your printer. Control-C or Control Break Aborts current DOS command. USEFUL! Control-H or backspace removes last character typed Control-P or Control-PrtSc sends output to printer until turned off by typing same key combination (Control P) a second time. Whatever appears on screen will be sent to printer until turned off with control P a second time. This is a little used, often forgetten and HIGHLY useful key combination! Control Numlock or Control S pauses screen output. Press any key to continue Control-Alt-Delete keys together shuts down computer and WIPES OUT all computer data! This is also called a "warm boot" as compared to a cold boot (completely turning off computer, then turning back on again.) Either of these methods means that ALL DATA AND PROGRAMS LOST from RAM memory but whatever data stored on disk(s) remains. Other keys have special meanings and can be confused with their look-alike twins: the slash (/) and Backslash (\) are different but easily confused as are the apostrophe (') and grave accent (`), and also the capital O and Zero (0.) ---------------------------------------------------------------- ADDITIONAL DOS COMMANDS AND METHODS ---------------------------------------------------------------- Now on to some of the more advanced DOS commands, files and methods which we continue from the previous DOS tutorial: -- AUTOEXEC.BAT -- is not a DOS command but a small text file which gives the user an automatic way to specify a precise series of DOS commands whenever the computer is started each day. Within AUTOEXEC.BAT you can specify system variables such as the PATH and PROMPT commands, load or start a menu system with a variety of program choices, load memory resident "TSR" programs such as a calculator or notepad, run other batch files or start one specific program such as your word processor every time the computer is turned on. You can create or modify an AUTOEXEC.BAT file with any word processor which saves text in ASCII (plain text) format. Additional comments and explanations about the AUTOEXEC.BAT file are provided in the batch file tutorial elsewhere within PC-Learn. Following is a listing of the contents within a sample AUTOEXEC.BAT file. Note that it is simply a series of DOS commands which will be given every time the computer is first turned on. This list of autoexec.bat comamnds are only a sample, there are other variations which might be more appropriate for your computer. echo off date time path \dos;\wp;\util;\doc;\bat prompt $P$G verify on mode bw80,r type menu -- CONFIG.SYS -- is not a DOS command, but a small text file which tells DOS the system setup information or "custom configuration" of your computer. Whenever additional hardware is added such as a tape drive, mouse, ram drive or other device, you will usually add a DEVICE command to the CONFIG.SYS file so that DOS can recognize the new hardware or software device. Performance can also be increased by adding other parameters to the CONFIG.SYS file such as the FILES and BUFFERS commands. On startup, CONFIG.SYS helps DOS determine the configuration of hardware, RAM memory, keyboard, ramdisk, hard drives and other "customizations" to your system and is usually stored in the root or main directory of your hard drive. The CONFIG.SYS file can be prepared or altered with your word processor operating in ASCII mode (plain text). You could also use the COPY CON command or any text editor such as Edlin to prepare a CONFIG.SYS file. Following is a listing of the contents within a sample CONFIG.SYS file: device=ansi.sys device=vdisk.sys buffers=20 files=20 -- MODE -- (External) is a command to setup the printer, display and communications outputs of your computer. Use mode when you have several printers or two or more monitors such as both color and monochrome. Example: A>mode CO80 (set display mode to color,80 columns wide) Example: B>mode lpt1=com1 (set printer to com port number 1) Example: A>mode com1:10,n,8,1,p (set modem transmission settings) Example B>mode bw80,r (set monitor to b&w text, 80 columns wide) -- MORE -- (External) causes the display to pause when reading a long file or directory. More is always combined with other DOS commands. See below for an example using the MORE command. -- REDIRECTION AND PIPING -- Are not DOS commands but powerful methods for sending information to or through other DOS utilities. Some commands, for example DIR, can use MORE, SORT and other DOS "filters" with a special vertical bar | in a method called "piping". Piping is best explained as "filtering" a DOS action through yet another DOS program or command. Example A>dir|more (DIR listing is "piped" through MORE to pause after each screenful of information) Try it with a long listing! Example: B>type letter.txt|more (the file letter.txt is "piped" through MORE) -- < and > -- are input/output symbols. They help DOS send and receive signals properly. You can redirect the output from or towards a particular device. For example if the output of a file normally goes to the screen you could redirect it with the > symbol to the printer. Or you could redirect the input for a DOS command from a file, rather than the keyboard so you would not have to answer a series of questions - the file would provide the keystrokes. Example: A>sort<letter.txt>letter.new (sort letter.txt and output to a new file called letter.new) Example: B>dir>prn (meaning produce a directory listing, but send the output to the printer, rather than the screen) Example: format b:<special.txt (format a floppy and accept input keystrokes from the file special.txt rather than input from the keyboard so you don't have to answer yes/no or pause) These piping and redirection methods are powerful and subtle. -- SORT -- (External) sorts data lists in alphabetical or reverse order. It is frequently used with redirection and piping methods to sort directories, lists of text or to output its actions into a new file or directly to the printer. Example: A>dir|sort Example: sort<letter.doc>new.doc -- GRAPHICS -- (External) allows you to print the contents of a graphics display (e.g., a lotus graph on the screen) while using the SHIFT-PRTSC key combination mentioned earlier. Graphics mode software uses medium resolution CGA color displays or other graphics displays which will not print using the standard SHIFT- PRTSC key until the DOS graphics system has been loaded. Graphics is a memory resident program which uses some RAM memory. If a screen display will not print on your printer by tapping SHIFT-PRTSC, trying running graphics first then retry SHIFT-PRTSC. Example: A>graphics -- FIND -- (External) searches for words and phrases in a file. You cannot use wild cards (? and *). You must use quotes surrounding the phrase or word which is sought. Example: A>find "chocolate candy bars" letter.txt bones.wks (meaning: search for "chocolate candy bars" within the two files letter.txt and bones.wks then report any occurrences) -- ASSIGN -- (External) tells DOS to send disk requests for one drive to the other. Effectively renames your a drive the b drive and vice versa. Allows you to access only certain drives for security reasons (remote modem use, for example). By itself, assign simply restores the normal drive configurations and names. DISKCOPY and FORMAT commands ignore assign! Use of assign command is rare. Example: B>assign c=a -- PATH -- (Internal) tells DOS where to search for executable files in the subdirectories you specify. Allows simultaneous searching of many subdirectories at once. Path eliminates the need to search through many subdirectories manually. Frequently a PATH command is used in your autoexec.bat file when starting the computer. A path command is highly recommended for use with all hard drives and, as stated, is embedded within the AUTOEXEC.BAT file as a permanent command. Example: C>path \letters;\finance;\utils -- PROMPT -- (Internal) allows change of the DOS prompt - for example, the dull A> on screen. $P shows the active directory. $G shows the > symbol. This can be set in the main autoexec.bat file to initialize the prompt every time you start your computer. With the proper commands you can dramatically change your prompt to even display words, pictures or phrases rather than a typical C> See batch file tutorial covered later. Example: A>prompt $P$G. (result is: a:\> ) -- TREE -- (External) shows the structure of the subdirectories on your disk. You can check the arrangement of the root (main) and all subdirectories. Tree/f shows all file names. Example: B>tree/f -- ATTRIB -- (External) allows a file to be set as "read only" (non-erasable). Attrib +r marks for read only. Attrib -r removes this. Protects files from modification or removal. Attrib alone displays file attributes. A small r appears to the left of a files directory listing if that file is read only (protected). Only available in DOS 3.0 and later. Example: A>attrib +r letters.doc -- BACKUP & RESTORE -- (External) used to making spare copies (backups) of hard disk data. Copies groups of files to floppies. Restore reverses the process and puts the files from floppies to hard disk. Backup/m copies only files modified since the last backup. Backup/s copies all subdirectories and their files. Backup/d copies files modified after the date you specify. Backup/a adds files to a disk that already contains other files. Files copied to floppies with backup can't be used (they are "encoded") until they are restored ("unencoded"). Restore/s puts back all subdirectory files. Example: A>backup c:\*.* a:/s Example: C>restore a:\*.* c:/s -- EDLIN -- (External) is a small word processor/text editor which prepares text files. DOS version 5.0 uses an upgraded text editor called EDIT which is easier to use the Edlin. Edlin's output is ASCII (plain text). Edlin is rudimentary and provides editing line by line. Other word processors and text editors can output ASCII files more quickly and easily, but Edlin is good for short jobs such as preparing batch files. The COPY CON command (discussed earlier) will do the job also. The entire list of Edlin commands is detailed in your DOS manual. Example: A>edlin go.bat (starts Edlin and loads the file go.bat) -- RAMDRIVE.SYS -- (used in MS-DOS, see below) (External) -- VDISK.SYS -- (used in PC-DOS, see below) (External) Both of the above files are equivalent "ramdisks" which allow you to construct an artificial software disk drive in RAM computer memory. It is very fast and is also known as a virtual disk. RAMDRIVE.SYS or VDISK.SYS is usually placed in the CONFIG.SYS file via the DEVICE command. RAMDRIVE.SYS or VDISK.SYS is available in DOS 3.0 and later. DOS 2.0 users can use alternative "add in" RAMDISK utilities to produce the same result. Within the CONFIG.SYS file the following statement might appear for users of this device: Example: device=vdisk.sys 128 (sets up a ramdisk of 128,000 bytes in size) Tutorial finished. Have you registered PC-Learn to receive your bonus disks? Registration is encouraged. Shareware works on the honor system! Send $25 to Seattle Scientific Photography, Department PCL6, PO Box 1506, Mercer Island, WA 98040. Latest version of PC-Learn and two bonus disks shipped promptly!