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Ch 111 Chapter 11 Advanced Batch Files
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Ch 112 Overview This 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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Ch 113 Batch File Commands Batch files must … have the file extension.BAT be an ASCII text file include legitimate commands
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Ch 114 Batch File Commands Any command used at the command line can be used in a batch file.
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Ch 115 Batch File Commands Batch files have … a limited vocabulary ( commands ) a syntax programming logic
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Ch 116 A Review of the REM, PAUSE, and ECHO Commands REM command (remarks)… statements keyed in by user that tell what is the purpose of the batch file.
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Ch 117 A Review of the REM, PAUSE, and ECHO Command PAUSE command … instructs the batch file to stop executing until the user takes some action.
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Ch 118 A Review of the REM, PAUSE, and the ECHO Command Two ways to interrupt a batch file during execution: Ê Press + C Ë Press +
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Ch 119 A Review of the REM, PAUSE, and the ECHO Command ECHO command … displays a command and the output of that command to the screen.
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Ch 1110 A Review of the REM, PAUSE, and the ECHO Command When ECHO is ON: all commands in a batch file are displayed on the screen.
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Ch 1111 A Review of the REM, PAUSE, and the ECHO Command When ECHO is OFF … can see the output of the command, but not the command itself.
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Ch 1112 Advanced Features of ECHO and REM To save valuable processing time, use a double colon (::) instead of the REM command.
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Ch 1113 Advanced Features of ECHO and REM To delete the display of even the message “ 1 file(s) copied ”, use the device NUL.
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Ch 1114 Advanced Features of ECHO and REM Using NUL will not suppress a message such as “file not found”.
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Ch 1115 Advanced Features of ECHO and REM To suppress all messages use the command CTTY NUL.
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Ch 1116 Advanced Features of 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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Ch 1117 Advanced Features of ECHO and REM There is no such thing as a blank line in batch files.
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Ch 1118 Advanced Features of ECHO and REM To insert a blank line, key in ECHO followed by a period (ECHO.)
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Ch 1119
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Ch 1120 The GOTO Command GOTO command … will branch to a new line, creating a loop works in conjunction with a label
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Ch 1121 The GOTO Command A loop will repeat steps until it is stopped by … using an IF statement breaking into the batch file with + C
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Ch 1122 The GOTO Command A label … is preceded by a colon (:) can be no longer than 8 characters is not a command
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Ch 1123 The GOTO Command GOTO has one parameter … GOTO label
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Ch 1124
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Ch 1125 The SHIFT Command The SHIFT command allows for an unlimited number of parameters on the command line.
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Ch 1126 The SHIFT Command SHIFT command … changes the position of the replaceable parameter in a batch file.
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Ch 1127
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Ch 1128 The IF Command IF command … allows for conditional processing.
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Ch 1129 The IF Command Conditional processing … compares two items to determine if they are identical, or if one is greater than the other.
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Ch 1130 The IF Command The result of comparison testing is either a True or False value.
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Ch 1131 The IF Command True = items are identical False = items are not identical
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Ch 1132 The IF Command Syntax of IF command: IF
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Ch 1133 The 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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Ch 1134 The IF Command The IF command checks for three conditions.
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Ch 1135 IF Command Using Strings To test whether or not one character string is exactly the same as another, use the IF command.
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Ch 1136 IF Command Using Strings The strings to be compared are separated by two equal signs (= =).
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Ch 1137
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Ch 1138 Testing for NULL Values In a batch file it is sometimes possible to be caught in an endless loop.
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Ch 1139 Testing for NULL Values A value equal to “nothing” must be placed in a batch file to indicate when to end.
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Ch 1140 Testing for NULL Values NULL values … a user-defined value equivalent to nothing (no data).
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Ch 1141 Testing for NULL Values Testing for a null value involves using the IF command with quotation marks.
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Ch 1142 Testing for NULL Values Use quotation marks to test for null value: IF “%1” = = GOTO LABEL
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Ch 1143 Testing for NULL Values “If nothing is there, GOTO somewhere else”
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Ch 1144
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Ch 1145 The IF EXIST/IF NOT EXIST Command IF EXIST/IF NOT EXIST command: checks for the existence or non-existence of a file.
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Ch 1147 The IF ERRORLEVEL Command Testing Exit code … a code set by a program that indicates a True or False condition when the program finishes executing.
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Ch 1148 The IF ERRORLEVEL Command Testing IF ERRORLEVEL command… a statement in a batch file that can test exit codes.
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Ch 1149 The IF ERRORLEVEL Command Testing An exit code is tested with ERRORLEVEL to determine if it is greater than or equal to it.
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Ch 1150
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Ch 1151 Writing Programs to Test for Key Codes Exit codes can be … set by an operating system program created by writing a small program
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Ch 1152 Writing Programs to Test for Key Codes To write a program a user can … use a programming language use an OS utility called DEBUG
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Ch 1153 Writing Programs to Test for Key Codes Easiest way to use DEBUG is to create a script file.
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Ch 1154 Writing Programs to Test for Key Codes Script file … a set of instructions that can be written in any text editor.
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Ch 1155
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Ch 1156 The CHOICE Command CHOICE command … prompts the user to make a choice.
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Ch 1157 The CHOICE Command Syntax for CHOICE command: CHOICE [/C[:]choices] [/N] [/S] [/T[:]c,nn] [text]
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Ch 1158
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Ch 1159 The 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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Ch 1160 The Environment Application programs can … read any items in the environment post their own messages there
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Ch 1161 The Environment A user can leave a message there through … the AUTOEXEC.BAT file other batch files the command line
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Ch 1162 The Environment To leave a message, use the SET command.
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Ch 1163 The Environment Syntax for SET command … SET [ variable = [string] ]
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Ch 1165 The DIRCMD Environmental Variable The DIRCMD command variable allows the user to preset, or change the way DIR displays information.
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Ch 1166
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Ch 1167 The FOR..IN..DO Command The FOR..IN..DO command can be … issued at the command line placed in a batch file
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Ch 1168 The FOR..IN..DO Command FOR allows the use of a single command to issue several commands at once.
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Ch 1169 The FOR..IN..DO Command Syntax for the FOR..IN..DO command at the command line: FOR %variable IN (set) DO command [command-parameters]
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Ch 1170 The FOR..IN..DO Command Syntax for the FOR..IN..DO command in a batch program: FOR %variable IN (set) DO command [command-parameters]
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Ch 1171
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Ch 1172 The CALL Command CALL command … calls (executes) one batch program from another without causing first batch program to stop.
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Ch 1173
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