Advanced%20Batch%20Files

1
Chapter 11

• Advanced Batch Files

2
Overview

• Quick review of batch file commands learned in
  earlier chapters.

3
Overview

• Advanced features of these commands will be
  explained and used.

4
Overview

• Will explain the purpose and function of
  remaining batch file commands and then will use
  these commands to write sophisticated batch
  files.

5
Overview

• Will refine techniques in working with
  environment.

6
Batch File Commands

• Batch files
• Have file extension .BAT or .CMD
• Are ASCII text files
• Include legitimate commands
• Create generic batch files using replaceable
  parameters
• Are not case sensitive

7
Batch File Commands

• Any command used at the command line can be used
  in a batch file.

8
Batch File CommandsTable 11.1 Batch File
Commands p. 548

9
Batch File CommandsTable 11.1 Batch File
Commands p. 548
10
Batch File Commands

• Batch files have
• Limited vocabulary (commands)
• Syntax
• Programming logic

11
Review of REM, PAUSE, and ECHO Commands

• REM command (remarks)
• Documents batch file
• Not a command that executes
• With ECHO ON displays but does not execute what
  follows REM
• Placed at beginning of a line in batch or
  CONFIG.SYS file, REM disables but does not delete
  line

12
Review of REM, PAUSE, and ECHO Commands

• PAUSE command
• Instructs batch file to stop executing until user
  takes some action
• Does not stop execution of .EXE or COM program
• Will not do any conditional processing

13
Review of REM, PAUSE, and ECHO Commands

• To interrupt a batch file during execution
• Press ltCtrlgt C
• Press ltCtrlgt ltBreakgt

14
Review of REM, PAUSE, and ECHO Commands

• ECHO command
• Used on command line or in batch file
• Controls printing of messages on screen when
  batch file run

15
Review of REM, PAUSE, and ECHO Commands

• ECHO ON -displays all commands to screen along
  with output.
• ECHO OFF - displays only output of commands to
  the screen.
• Precede ECHO OFF with _at_ and ECHO OFF will not
  appear on screen.

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Advanced Features of ECHO and REM

• For faster processing, use a double colon ()
  instead of REM in front of remark or
  documentation line.

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Advanced Features of ECHO and REM

• To delete the display of even the message 1
  file(s) copied, redirect output of command to
  NUL device.

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Advanced Features of ECHO and REM

• Using NUL will not suppress a message such as
  file not found.

19
Advanced Features of ECHO and REM

• There is no such thing as a blank line in batch
  files.
• Pressing ltEntergt does not generate a blank line
  in batch files.

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Advanced Features of ECHO and REM

• To insert a blank line, key in ECHO followed by a
  period (ECHO.)

21
ActivityUsing ECHO and NUL

• KEY CONCEPTS
• Replaced REM with () for faster processing
• Redirected output to NUL device so no
  messages/remarks shown on screen
• _at_ before ECHO OFF - ECHO OFF does not appear
  on screen
• ECHO. created a blank line in batch file

22
The GOTO Command

• GOTO command
• In conjunction with a label creates a loop
• Processes command following label

23
The GOTO Command

• Loop repeats steps until stopped by . . .
• using an IF statement.
• breaking into the batch file with ltCtrlgt C.

24
The GOTO Command

• Label in a batch file
• Is not a command
• Identifies location in a batch file
• Is preceded by a colon ()
• No longer then 8 characters
• Not case sensitive
• Ignored by OS until called with GOTO command

25
The GOTO Command

• GOTO has one parameter
• GOTO label

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ActivityUsing the GOTO Command

• KEY CONCEPTS
• Debug - see and repair any errors
• To execute a batch file must be at system prompt
  (not in editor)
• Usefulness of loops
• Redirecting output to NUL device

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ActivityUsing the GOTO Command

• Example of a Batch file to delete
• all files from many floppy disks
• _at_ECHO OFF
• TOP
• CLS
• ECHO Place disk with files no longer want in ECHO
  Drive A.
• PAUSE
• DEL /Q A.\
• ECHO Press Ctrl C to stop executing this batch
  file.
• ECHO otherwise, press any key to continue
  deleting files.
• PAUSE gt NUL
• GOTOTOP

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The SHIFT Command

• SHIFT command allows for an unlimited number of
  parameters on the command line.

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ActivityUsing the Shift Command
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ActivityUsing the Shift Command
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ActivityUsing the Shift Command
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ActivityUsing the Shift Command
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ActivityUsing the Shift Command

• KEY CONCEPTS
• Can keep date log not dependent on file
  modification date
• Usefulness of SHIFT command
• Displays 5 or more parameters and places echoing
  parameters in batch file
• Moves each parameter over by one position
• ECHO - echoes what is keyed in

34
ActivityUsing the Shift Command

• KEY CONCEPTS
• sign tells OS to concatenate files
• Contents of file ended when see EOF
• Typically ltCtrlgt Z
• COPY command places second ltCtrlgt Z at end of
  file creates problem
• Solve by copying file in binary mode

35
ActivityUsing the Shift Command

• KEY CONCEPTS
• /B switch - tells OS to copy file in binary
  mode
• Concatenated files with no switches - files
  copied in text mode
• gtgt used to see both name of directory and bytes
  in directory.
• ltCtrlgt C used to break out

36
The IF Command

• IF command allows for conditional processing of
  parts of a batch file.
• Conditional processing compares two items to
  determine if they are identical.

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The IF Command

• Results of comparison testing
• True
• Items are identical
• Command executed
• False
• Items are not identical
• Command not executed
• Goes to next command line in batch file

38
The IF Command

• IF command checks to see
• If two sets of characters are/are not identical
• If a file exists
• The value of the variable in ERRORLEVEL

39
The IF Command

• IF command syntax
• IF ltconditiongt ltcommandgt
• IF NOT ERRORLEVEL number command
• IF NOT string1string2 command
• IF NOT EXIST filename command
• Note complete syntax in Appendix H

40
The IF Command Using Strings

• IF can be used to compare strings.
• Two equal signs ( ) separate items to be
  compared.

41
The IF Command Using Strings

• Can tell IF statement to GOTO a label or to
  perform an operation whether the condition is
  true or false.

42
ActivityUsing the IF Command with Strings

• KEY CONCEPTS
• No more lines - return to system prompt
• Batch file replaceable parameters get value from
  position on command line
• Case matters
• To ignore case add the /I parameter immediately
  following the IF statement

43
Testing for NULL Values

• If SHIFT used in a batch file will be caught in
  endless loop when all parameters are used.

44
Testing for NULL Values

• A null value (value equal to nothing) must be
  placed in a batch file to indicate end of data.

45
Testing for NULL Values

• Can test for a NULL value using IF with quotation
  marks.
• IF 1 GOTO LABEL

46
Testing for NULL Values

• Can test for a NULL value using
• IF with any word.
• IF 1word word GOTO LABEL
• wordword

47
Testing for NULL Values

• Can test for a NULL value using
• IF with backslash.
• IF \1\ \\ GOTO LABEL
• \\\\

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ActivityUsing NULL Values

• KEY CONCEPTS
• Test for a null value using quotation marks
• Test for null value using a user designated word

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The IF EXIST/IF NOT EXIST Command

• IF EXIST/IF NOT EXIST command
• Checks for the existence or non-existence of a
  file
• Works only with file names - not directory names

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The IF EXIST/IF NOT EXIST Command

• Using IF EXIST command
• If file does exist
• Condition - true
• Processing passes to specified GOTO location
• If file does not exist
• Condition - false
• Batch file reads next line in file

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The IF EXIST/IF NOT EXIST Command

• Using IF NOT EXIST command
• If file does not exist
• Condition - true
• Processing passes to specified GOTO location
• If file does exist
• Condition -false
• Batch file reads next line in file

52
ActivityUsing IF EXIST to Test for a File

• 1. IF \1\ \\ GOTO end
• 2. IF NOT \2\ \\ GOTO next
• 3. ECHO You must include a destination name
• 4. ECHO for the new directory name.
• 5. GOTO end
• 6. next

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ActivityUsing IF EXIST to Test for a File

• 7. IF EXIST 1 GOTO message
• 8. REN 1 2
• 9. GOTO end
• 10. message
• 11. ECHO This is a file, not a directory.
• 12. end

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ActivityUsing IF EXIST to Test for a File

• KEY CONCEPTS
• IF command testing for true condition
• True condition - command processed
• False condition - command ignored - next line in
  batch file processed
• IF NOT command testing for truth in reverse
• False condition - command processed
• True condition - command ignored - next line in
  batch file processed

55
ActivityUsing IF EXIST to Test for a File

• KEY CONCEPTS
• IF EXIST
• Used to check for existence of a file
• Can not be used to check for existence of a
  directory
• Use NUL to fool IF EXIST/IF NOT EXIST to check
  for existence of directory

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The IF ERRORLEVEL Command Testing

• Program can set an exit code when it finishes
  executing.
• Batch file tests exit code with IF ERRORLEVEL
  statement.

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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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The IF ERRORLEVEL Command Testing

• Exit codes listed in descending order when using
  IF ERROR LEVEL.
• Exit codes listed in ascending order when using
  IF NOT ERORLEVEL.

59
ActivityUsing IF ERRORLEVEL with COPY

• KEY CONCEPT
• User exit codes successfully in a batch file

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Writing Programs to Test for Key Codes

• Exit codes
• Set by an operating system program
• Created by writing small program based upon an
  activity

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Writing Programs to Test for Key Codes

• Every time a key is pressed, it is identified by
  a scan code.

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Writing Programs to Test for Key Codes

• Can write programs by using
• Programming language
• DEBUG (operating system utility program)

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Writing Programs to Test for Key Codes

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

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Writing Programs to Test for Key Codes

• A script file is set of instructions that can be
  written in any text editor.

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Writing Programs to Test for Key Codes

• Feed script file via redirection into DEBUG
  program.
• DEBUG program converts script file to executable
  program with .com file extension.

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Writing Programs to Test for Key Codes

• Summary of command available
• within BUG program (p. 576)
• assemble A (Address)
• compare C range address
• dump D (range)
• enter E address (list)
• fill F range list
• go G address addresses
• hex H value1 value2
• input I port
• load L address drive firstsector number
• move M range address
• name N pathname arglist
• output O port byte

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Writing Programs to Test for Key Codes

• Summary of command available
• within BUG program (p. 576)
• proceed P addressnumber
• quit Q
• register R register
• search S range list
• trace T address value
• unassemble U range
• write W address drive firstsector
  number
• allocate expanded memory XA pages
• deallocate expanded memory XD handle
• map expanded memory pages XM Lpage Ppage
  handle
• display expanded memory status XS

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Writing Programs to Test for Key Codes

• .COM Program Written with DEBUG
• to return scan code of Pressed Key
• A\gtDEBUG
• -a 100 ltEntergt
• 158E0100 mov ah,8 ltEntergt
• 158E0102 int 21 ltEntergt
• 158E0104 cmp al,0 ltEntergt
• 158E0106 jnz 10a ltEntergt
• 158E0108 mov ah,8int21 ltEntergt
• 158E010A mov ah,4c ltEntergt
• 158E010C int 21 ltEntergt
• 158E010E mov ah,8 ltEntergt
• -r cx ltEntergt
• CX 0000
• e ltEntergt
• -n reply.com ltEntergt
• -w ltEntergt
• Writing 000E bytes

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Writing Programs to Test for Key Codes

• Easier way to create reply.com is to create
  script file with any text editor
• Script file - text file containing series of
  commands that can be redirected into DEBUG to
  create a .COM file
• Script file is not the program

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ActivityWriting a Script File

• KEY CONCEPTS
• Convert script file into a program by redirecting
  it to DEBUG
• Error codes tested for equal to or greater than
  value specified
• IF ERRORLEVEL - descending order
• IF NOT ERROR LEVEL - ascending order

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The Environment

• The environment is an area in memory where data
  can be stored.

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The Environment

• Data
• Constant/fixed values - never change
• Variables that do change - depends on conditions
  or information passed to program

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The Environment

• In programming, an expression is any legal
  combination of symbols that represent a value.

74
The Environment

• The operating system stores data in form of two
  strings
• Name of variable
• Value of variable

75
The Environment

• Environmental variable is name assigned to string
  (value) of data.

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The Environment

• User can set environmental variables.
• Some common variables set when Windows started.

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The Environment

• User can leave messages in environment using SET
  command.

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The Environment

• Environmental variables set in Command Prompt
  window or batch files executed in Command Prompt
  window remain in effect only during that command
  prompt session.

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The Environment

• SET syntax
• SET variable string

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The Environment

• SET without parameters displays current
  environmental variables.

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ActivityUsing SET and the Environmental Variables

• KEY CONCEPTS
• Command processor must be in memory when keying
  in command
• Using MORE
• Pressing ltEntergt - moves one line at a time
• Pressing ltSpaceBargt - goes to end of file
• SET with letter of alphabet - environmental
  variables beginning with letter displayed

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ActivityUsing SET and the Environmental Variables

• KEY CONCEPTS
• To see value of environmental variable - use
  ECHO and enclose environmental variable name you
  are seeking with percent signs
• Environmental variable
• Can be used with commands
• Can be used to change directories

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Using SET and the Environment in Batch Files

• Can use built-in environmental variables that
  Windows sets and uses.
• Can set own environmental variables.

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Using SET and the Environment in Batch Files

• Setting environmental variables
• Can give them name and value in batch
  file/command line
• Only good for that session of Command Prompt
  Window

85
ActivityUsing SET and the Environment in Batch
Files

• KEY CONCEPTS
• Can set environmental value and use it in batch
  file
• Environmental variables set - deleted when
  Command Prompt window closed
• Environmental variables - not case sensitive
• To eliminate value - must set it at nothing
• Can add directory to PATH statement

86
The DIRCMD Environmental Variable

• DIRCMD environmental variable with
• SET to preset DIR command parameters or switches.
• ERRORLEVEL to change the way DIR displays
  information for current MS-DOS work session.

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ActivityUsing DIRCMD

• KEY CONCEPTS
• Can determine how to display batch files
• Files displayed this way until change values or
  close Command Prompt session

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FORINDO Command

• FOR..IN..DO command
• Allows repetitive processing
• Can be
• issued at the command line
• placed in a batch file

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FORINDO Command

• FOR allows the use of a single command to issue
  several commands at once.
• Command can DO something FOR every value IN a
  specified set.

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FORINDO Command

• Syntax at command line
• FOR variable IN (set) DO
• command command-parameters

91
FORINDO Command

• Syntax in a batch program
• FOR variable IN (set) DO
• command command-parameters

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FORINDO Command

• GOTO loop is vertical.
• FORINDO loop is horizontal.

93
FORINDO Command

• There is a difference between
• a variable and a parameter.

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ActivityUsing the FORINDO Command

• KEY CONCEPTS
• Space and comma between items in a set work same
  way
• Advantages of using space and comma between items
  in a set
• Command line is case sensitive
• Variable letter chosen is not important
• - used at command line
• used in batch file

95
ActivityUsing the FORINDO Command

• KEY CONCEPTS
• Items in set is a horizontal not vertical loop
• Moved all batch files to BATCH subdirectory and
  set path to include BATCH directory
• Caution If close Command Prompt window, have
  to issue following command to include the
  A\BATCH directory in your path
  A\BATCHgtA\BATCH\ADD A\BATCH
• Changed dates of files

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More Features of the FORINDO Command

• New features of FORINDO command
• May list environmental variables so they are
  divided and appear on separate lines
• Use /R parameter (recursive parameter)

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More Features of the FORINDO Command

• New features of FORINDO command
• Use tilde operator () to
• Strip a file name of quotation marks
• Expand variable
• Select specific text from ASCII files

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ActivityUsing Additional Features of FORINDO
Command

• KEY CONCEPTS
• Use FORINDO to display list one line at a time
  (list easier to read)
• Tilde () strips file name of quotation marks
• Use quotation marks to add prefix or suffix to
  long file name
• REN only needs file name

99
ActivityUsing Additional Features of FORINDO
Command

• KEY CONCEPTS
• Use n and x to precede any file name with prefix
• Can strip out specific fields in a text file -
  use /F parameter
• Can delimit data

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The CALL Command

• CALL command
• Allows you to run one batch file from within
  another
• Returns control to original batch file when
  second batch file is finished executing

101
ActivityUsing CALL

• KEY CONCEPTS
• Use ltCtrlgt L - to eject a page
• Use ltCtrlgt G - to create a noise
• Create series of batch files that return to
  directory you were previously in
• When executing a program within a batch file -
  not returned to batch file unless you use CALL

102
ActivityUsing CALL

• KEY CONCEPTS
• Creating and Saving batch file called HOMETO.BAT
  in BATCH directory
• Line 1 COPY A\BATCH\HOME.DAT
  A\BATCH\HOMESAVE.BAT ltEntergt
• Line 2 CD gtgt A\BATCH\HOMESAVE.BAT ltEntergt
• Line 3CALL HOMNESAVE.BAT ltEntergt
• Line 4 DEL A\BATCH\HOMESAVE.BAT ltEntergt