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Chapter 11Chapter 11

Advanced Batch Files

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OverviewOverviewThis chapter focuses on batch file commands that allow you to: write sophisticated batch

files further refine your technique in working with the environment

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Batch File Batch File CommandsCommands

Batch files must … have the file extension .BAT be an ASCII text file include legitimate commands

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Batch File Batch File CommandsCommands

Any command used at the command line can be used

in a batch file.

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Batch File Batch File CommandsCommands

Batch files have … a limited vocabulary (commands) a syntax programming logic

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A Review of the A Review of the REMREM, , PAUSEPAUSE, and , and ECHOECHO

CommandsCommands

REM command (remarks)…statements keyed in by user that tell what is the purpose of the batch

file.

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A Review of the A Review of the REMREM, , PAUSEPAUSE, and , and ECHOECHO

CommandCommand

PAUSE command …instructs the batch file

to stop executing until the user takes some action.

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A Review of the A Review of the REMREM, , PAUSEPAUSE, and the , and the ECHOECHO

CommandCommand

Two ways to interrupt a batch file during execution:

Press <Ctrl> + C Press <Ctrl> + <Break>

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A Review of the A Review of the REMREM, , PAUSEPAUSE, and the , and the ECHOECHO

CommandCommand

ECHO command …displays a command

and the output of thatcommand to the screen.

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A Review of the A Review of the REMREM, , PAUSEPAUSE, and the , and the ECHOECHO

CommandCommand

When ECHO is ON: all commands in a batch file are displayed on the screen.

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A Review of the A Review of the REMREM, , PAUSEPAUSE, and the , and the ECHOECHO

CommandCommand

When ECHO is OFF … can see the output of the command, but not the command itself.

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Advanced Features Advanced Features of of ECHOECHO and and REMREM

To save valuable processing time, use a double colon (::)

instead of the REM command.

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Advanced Features Advanced Features of ECHO and REMof ECHO and REM

To delete the display of even the message “1 file(s)

copied”, use the device NUL.

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Advanced Features Advanced Features of ECHO and REMof ECHO and REM

Using NUL will not suppress a message such

as “file not found”.

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Advanced Features Advanced Features of ECHO and REMof ECHO and REM

To suppress all messages use the command CTTY

NUL.

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Advanced Features Advanced Features of ECHO and REMof ECHO and REM

When CTTY NUL is used, must follow with CTTY

CON in order to have control of the console.

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Advanced Features Advanced Features of ECHO and REMof ECHO and REM

There is no such thing as a blank line in batch files.

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Advanced Features Advanced Features of ECHO and REMof ECHO and REM

To insert a blank line, key in ECHO followed by a

period (ECHO.)

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Activity:Activity: Using ::,Using ::,ECHOECHO, , CTTYCTTY, and, and

NULNUL

. . .

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The GOTO The GOTO CommandCommand

GOTO command … will branch to a new line, creating a loop works in conjunction with a label

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The GOTO The GOTO CommandCommand

A loop will repeat steps until it is stopped by …

using an IF statement breaking into the batch file with <Ctrl> + C

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The GOTO The GOTO CommandCommand

A label … is preceded by a colon (:) can be no longer than 8 characters is not a command

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The GOTO The GOTO CommandCommand

GOTO has one parameter … GOTO label

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Activity:Activity: Using theUsing theGOTO CommandGOTO Command

. . .

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The SHIFT The SHIFT CommandCommand

The SHIFT command allows for an unlimited

number of parameters on the command line.

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The SHIFT The SHIFT CommandCommand

SHIFT command …changes the position of the replaceable

parameterin a batch file.

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Activity:Activity: Using theUsing theSHIFT CommandSHIFT Command

. . .

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The IF CommandThe IF Command

IF command …allows for conditional

processing.

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The IF CommandThe IF Command

Conditional processing …compares two items to determine if they areidentical, or if one isgreater than the other.

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The IF CommandThe IF Command

The result of comparison testing is either a True or

False value.

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The IF CommandThe IF Command

True = items are identical

False = items are not identical

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The IF CommandThe IF Command

Syntax of IF command:

IF <condition> <command>

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The IF CommandThe IF Command

If a condition is True, the command will be executed.

If a condition is False, the command will not be executed.

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The IF CommandThe IF Command

The IF command checks for three conditions.

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IF Command IF Command Using StringsUsing Strings

To test whether or not one character string is exactly the same as another, use

the IF command.

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IF Command IF Command Using StringsUsing Strings

The strings to be compared are separated by two

equal signs (= =).

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Activity:Activity: Using theUsing theIF Command withIF Command with

StringsStrings

. . .

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Testing for NULL Testing for NULL ValuesValues

In a batch file it is sometimes possible to be caught in an endless loop.

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Testing for NULL Testing for NULL ValuesValues

A value equal to “nothing” must be placed in a batch file to indicate when to

end.

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Testing for NULL Testing for NULL ValuesValues

NULL values …a user-defined value

equivalent to nothing (no data).

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Testing for NULL Testing for NULL ValuesValues

Testing for a null value involves using the IF

command with quotation marks.

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Testing for NULL Testing for NULL ValuesValues

Use quotation marks to test for null value:

IF “%1” = = GOTO LABEL

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Testing for NULL Testing for NULL ValuesValues

“If nothing is there, GOTO somewhere else”

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Activity:Activity: UsingUsingNull ValuesNull Values

. . .

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The IF EXIST/IF NOT The IF EXIST/IF NOT EXIST CommandEXIST Command

IF EXIST/IF NOT EXIST command:

checks for the existence or non-existence of a

file.

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Activity:Activity: Using IFUsing IFEXIST to Test for aEXIST to Test for a

FileFile

. . .

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The IF ERRORLEVEL The IF ERRORLEVEL Command TestingCommand Testing

Exit code …a code set by a program

that indicates a True or False condition when

the program finishesexecuting.

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The IF ERRORLEVEL The IF ERRORLEVEL Command TestingCommand Testing

IF ERRORLEVEL command…a statement in a batch

file that can test exit codes.

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The IF ERRORLEVEL The IF ERRORLEVEL Command TestingCommand Testing

An exit code is tested with ERRORLEVEL to

determine if it is greater than or equal to it.

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Activity:Activity: Using Using IFIFERRORLEVELERRORLEVEL with with

XCOPYXCOPY

. . .

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Writing Programs to Writing Programs to Test for Key CodesTest for Key Codes

Exit codes can be … set by an operating system program created by writing a small program

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Writing Programs to Writing Programs to Test for Key CodesTest for Key Codes

To write a program a user can …

use a programming language

use an OS utility called DEBUG

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Writing Programs to Writing Programs to Test for Key CodesTest for Key Codes

Easiest way to use DEBUG is to create a script file.

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Writing Programs to Writing Programs to Test for Key CodesTest for Key Codes

Script file …a set of instructions that

can be written in any text

editor.

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Activity:Activity: Writing aWriting aScript FileScript File

. . .

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The CHOICE The CHOICE CommandCommand

CHOICE command …

prompts the user to make a choice.

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The CHOICE The CHOICE CommandCommand

Syntax for CHOICE command:

CHOICE [/C[:]choices] [/N] [/S][/T[:]c,nn] [text]

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Activity:Activity: UsingUsingCHOICECHOICE

. . .

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The EnvironmentThe Environment

The environment … is an area that the OS sets aside in memory holds important info. that the OS needs to know

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The EnvironmentThe Environment

Application programs can … read any items in the environment post their own messages there

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The EnvironmentThe EnvironmentA user can leave a message there through …

the AUTOEXEC.BAT file other batch files the command line

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The EnvironmentThe Environment

To leave a message, use the SET command.

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The EnvironmentThe Environment

Syntax for SET command …

SET [ variable = [string] ]

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Activity:Activity: Using SETUsing SETand the Environmentand the Environment

in Batch Filesin Batch Files

. . .

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The DIRCMD The DIRCMD Environmental Environmental

VariableVariable

The DIRCMD command variable allows the user to preset, or change the way DIR displays information.

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Activity:Activity: UsingUsingDIRCMDDIRCMD

. . .

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The FOR..IN..DO The FOR..IN..DO CommandCommand

The FOR..IN..DO command can be …

issued at the command line placed in a batch file

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The FOR..IN..DO The FOR..IN..DO CommandCommand

FOR allows the use of a single command to issue

several commands at once.

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The FOR..IN..DO The FOR..IN..DO CommandCommand

Syntax for the FOR..IN..DO command at the command line:

FOR %variable IN (set) DOcommand [command-parameters]

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The FOR..IN..DO The FOR..IN..DO CommandCommand

Syntax for the FOR..IN..DO command in a batch program:

FOR %%variable IN (set) DOcommand [command-parameters]

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Activity:Activity: Using theUsing theFOR..IN..DOFOR..IN..DO

CommandCommand

. . .

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The CALL The CALL CommandCommand

CALL command …calls (executes) one batch program from anotherwithout causing firstbatch program to stop.

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Activity:Activity: UsingUsingCALLCALL

. . .