Batch Files

Introduction

If there is a set of DOS commands that you use frequently, or someone else who doesn't know DOS needs to use them, the commands can be groped together in a BATCH file. The commands will then be executed in the order in which they appear in the file by typing a single command. Almost any DOS command can be used in a BATCH file.

BATCH Filenames

Batch files always have the file extension .BAT. You can choose any filename except one which is already used by DOS or another piece of software. MYFILE.BAT is a perfectly good filename. FORMAT.BAT is not (because there is a DOS program called format).

Running BATCH Files

To run a BATCH file you simply type its name - without the extension. So if you have a Batch file called MYFILE.BAT you would simply type MYFILE to run it.

Sample BATCH file

Here is a simple BATCH file listing:

REM FILENAME = TEST.BAT
REM This file clears the screen and lists
REM your current directory a screen at a time

CLS
DIR /P

Special BATCH commands

Nearly all ordinary DOS commands can be included in a BATCH file. In addition, there are some special commands which can only be used in a BATCH file. Some of these are :

REM
ECHO
PAUSE

REM

This is used to put comments in the batch file to make it easier to understand, e.g.:

REM Now get the next file.

ECHO

This is used either to write text to the screen during the running of the batch program or to suppress screen output.

If you don't have an ECHO command in your batch program all the commands in it will appear in the screen as the program runs. This is not always convenient

ECHO OFF - Turns off all the screen output except PAUSE and DOS messages.

ECHO ON - Restores printing of the screen output

If you want to suppress the ECHO OFF message do this :

@ECHO OFF

Any selected DOS command can be hidden from the screen with an @

e.g.

@DIR /W

PAUSE

This halts the running of the batch program to enable the user to take some action - changing a floppy disk for example. It also prompts the user to make this action e.g.:

PAUSE               Please put the disk in DRIVE A:

This will print the message
Please put the disk in DRIVE A: followed by
Press any key when ready….

ADVANCED BATCH FILES

The IF command is used to control the way the batch file runs depending on the circumstances.

User Parameters

When you type a parameter after a batchfile mane the parameter can be used within the batch file. Within the file itself %1 is used to specify parameter 1, %2 for parameter 2 etc.

Labels

Labels can be used in batchfiles. They always start with a ':' in the left hand column. You can jump to a label with the GOTO command.

Here is a very simple example showing the use of an IF statement a parameter and labels. It also shows the use of GOTO:

@ECHO OFF
REM             BATCH Program to show how parameters & if statements
REM             are used

IF "%1" == "YES" GOTO YES
ECHO You have NOT typed YES
GOTO FINISH

:YES
ECHO You have typed YES!

:FINISH
ECHO ON

Generate this as a batch file with a suitable name (TEST.BAT for example)

Try running the Batch file by typing TEST, then afterwards try running it by typing TEST YES. Try making the YES lowercase. What happens?

The FOR…DO command

This is used to repeat a series of DOS commands using parameters specified within the program.

The parameters are specified like this :

FOR %%a IN (PARAM1 PARAM2 PARAM3) DO etc…..

%%a becomes PARAM1 on the first pass, PARAM2 on the second pass, PARAM3 on the third pass. After the DO comes any valid DOS command. For example, to delete all files with the names TEMP.*, NEW.* and NEXT.*…

FOR &&a IN (TEMP NEW NEXT) DO DEL %%a.*

Instead of %%a you can also use %%b, %%c etc.

Computer Architecture

It is easily possible to control the colour of your screen and/or the position of the courser using batch files providing the ANSI.SYS screen driver is installed.

If you are using your machine at home you need the like:

DEVICE=C:\DOS\ANSI.SYS
or
DEVICE =C:\WINDOWS\COMMAND\ANSI.SYS in your CONFIG.SYS file

ANSI escape sequences

All ANSI escape sequences commence like this :

ESCape key, the [

This cannot be done directly from the DOS prompt since ESCape simply clears whatever you have just typed.

What you have to do is use the ECHO command to write the ESCape sequence to the screen from within a batch file

If you are using EDIT to generate the batch file, you need to hold the CTRL key down and press P, then ESCape. What appears on the screen when you do this is !.

Screen Codes

Here are the screen codes for the different colours, etc.

0   Default (white text, black background)
1   Bright text
5   Flashing text
6   Reverse text
8   Concealed text (Useful for passwords!)

30  Black text
31  Red text
32  Green text
33  Yellow text
34  Blue text
35  Magenta text
36  Cyan text
37  White text

40  Black background
41  Red background
42  Green background
43  Yellow background
44  Blue background
45  Magenta background
46  Cyan background
47  White background

Examples

The escape sequences need to be sent to the screen from a batch file using the ECHO command. Here are some examples:

• To set the system to show in Red, against a Green background
  ECHO [31;42m
• To reset the system to display the text in normal format
  ECHO [0m
• To set the system to show text in bright yellow and flashing
  ECHO [5;33m

In every case the is produces by holding CTRL and typing P, and then hitting the ESCape key. (in EDIT)

The following batch file is called SCREEN.BAT. enter and run It.

@Echo off
REM             Screen control batchfile which sets up colours
REM             Two parameters supplied
REM             First one is text colour
REM             Second one is background colour

REM deal with no parameters situation using flashing message in bold
IF "%1" == " " GOTO MESS1

REM else set text to desired colour, etc
Echo  [%1m

REM Deal with no second parameter
IF "%2" == " " GOTO FINISH

REM Else set Background colour
Echo  [%2m
GOTO FINISH

REM Write Flashing bright yellow error message
:MESS1
Echo  [5;33;1m
CLS
Echo                           NO PARAMETERS SUPPLIED!

REM Then reset to normal text and usual prompt
Echo  [0m
GOTO FINISH
:FINISH

You run the file by typing SCREEN followed by up tow numbers taken from the list above which set the text and background colours to what ever you want.

For example

SCREEN 31 43 - Gives you red text on a yellow background.

Try various numbers, and also see that happened if you forget to provide any, by just typing SCREEN.

Try out these! Write a batch file called NAME.BAT that writes your name in flashing bright red on the screen.
Write a batch file called BACK.BAT which makes all text appear in bright yellow against a red background.

Moving the cursor and re-assigning keys

Cursor position commands end with a A, B, C, D, or H and key assignments ones with a p.

Controlling Cursor Position

Remembering that the is obtained by pressing CTRL + P and then ESCape, here are some examples:

'A' moves the cursor up a specified number of lines:

ECHO [5Amarvin

This moves the cursor up 5 lines and then prints 'marvin' on the screen

'B' moves the cursor down a specified number of lines:

ECHO [7Bslarty

This moves the cursor down 7 lines and prints 'italic' in the screen

'C' moves the cursor right a specified number of columns

'D' moves the cursor left a specified number of spaces

'H' moves the cursor to a specified row and column position:

ECHO [13;40Hxrmx

This moves the cursor to row 13, column 40 and prints 'xrmx' on the screen

Reassigning Key

ECHO  ["a";"b"p

The following batch program called ATOB.BAT does both upper and lower case As:

@ECHO OFF
REM         Make the 'A' key in to a 'B' key

ECHO  ["A";"B"p
ECHO  ["a";"b"p

N.B. Make sure you make a BTOA.BAT file as well other wise you will need to reboot your computer to get back A

Programming the function Keys

The Functions keys F1 to F12

These are so-called soft keys and are often programmed to provide special functions.

These keys have special 'extended' codes both when used alone and when combined with SHIFT, CTRL or ALT. Here is the list:

How to Program a function key

You simply use the usual ESCape sequence. For example, suppose you want to press F10 instead of typing DIR/p:

ECHO [0;68;"DIR/p";13p

The 13 at the end is an ENTER. If you don't put this in, you will need to press ENTER after F10.

An Example

Here is a batch program that reassigns two Function keys and gives you a menu:

@ECHO OFF
REM     Reassign F1 to list current directory
REM     Reassign F10 to give DOS version

ECHO [0;59;"DIR/w/p";13p
ECHO [0;68;"VER";13p

REM     Now Put a menu on the Screen in Bright Yellow
CLS
ECHO [1;33m
ECHO [12;20HF1                   List Current directory
ECHO [14;20HF10                  Print DOS Version Number

REM     Reset display to normal
ECHO [0m

Type this file in (menu1.bat) and run it. Press F1. This will give a directory listing. Press F10. The DOS Version will be displayed.