Advanced Batch
Files
Ch 11
1
Overview
Quick review of batch file
commands learned in earlier
chapters.
Ch 11
2
Overview
Advanced features of these
commands will be explained
and used.
Ch 11
3
Overview
Will explain the purpose and
function of remaining batch file
commands and then will use these
commands to write sophisticated
batch files.
Ch 11
4
Overview
Will refine techniques in
working with environment.
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5
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
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Batch File Commands
Any command used at the
command line can be used in a
batch file.
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Batch File Commands
Table 11.1 Batch File Commands p. 548
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Batch File Commands
Table 11.1 Batch File Commands p. 548
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Batch File Commands
Batch files have:
 Limited vocabulary (commands)
 Syntax
 Programming logic
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10
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
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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
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Review of REM, PAUSE,
and ECHO Commands
To interrupt a batch file during
execution:
 Press <Ctrl> + C
 Press <Ctrl> + <Break>
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13
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
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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 @ 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”.
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Advanced Features of
ECHO and REM
 There is no such thing as a blank
line in batch files.
 Pressing <Enter> does not generate
a blank line in batch files.
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19
Advanced Features of
ECHO and REM
To insert a blank line, key in
ECHO followed by a period
(ECHO.)
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20
Activity—Using ECHO
and NUL
KEY CONCEPTS:
 Replaced REM with (::) for faster processing
 Redirected output to NUL device so no
messages/remarks shown on screen
 @ before ECHO OFF - “ECHO OFF” does
not appear on screen
 ECHO. created a blank line in batch file
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The GOTO Command
GOTO command:
 In conjunction with a label creates a
loop
 Processes command following label
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The GOTO Command
Loop repeats steps until stopped by . . .
 using an IF statement.
 breaking into the batch file with
<Ctrl> + C.
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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
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The GOTO Command
GOTO has one parameter:
 GOTO label
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Activity—Using 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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Activity—Using the
GOTO Command
Example of a Batch file to delete
all files from many floppy disks
@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 > 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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Activity—Using the
Shift Command
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Activity—Using the
Shift Command
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Activity—Using the
Shift Command
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Activity—Using the
Shift Command
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Activity—Using 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
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Activity—Using the
Shift Command
KEY CONCEPTS:
 + sign tells OS to concatenate files
 Contents of file ended when see EOF
 Typically <Ctrl> + Z
 COPY command places second <Ctrl> + Z at
end of file creates problem
 Solve by copying file in binary mode
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Activity—Using 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
 >> used to see both name of directory and
bytes in directory.
 <Ctrl> + C used to “break out”
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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
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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
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The IF Command
IF command syntax :
IF <condition> <command>
 IF
[NOT] ERRORLEVEL number command
 IF [NOT] string1==string2 command
 IF [NOT] EXIST filename command
 Note:
complete syntax in Appendix H
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The IF Command
Using Strings
 IF can be used to compare
strings.
 Two equal signs (= = ) separate
items to be compared.
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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.
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Activity—Using 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
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Testing for NULL Values
If SHIFT used in a batch file
will be caught in endless loop
when all parameters are used.
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Testing for NULL Values
A null value (value equal to
“nothing”) must be placed in a
batch file to indicate end of
data.
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Testing for NULL Values
Can test for a NULL value using
IF with quotation marks.
IF “%1” = = GOTO LABEL
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45
Testing for NULL Values
Can test for a NULL value using
IF with any word.
IF %1word = = word GOTO LABEL
word==word
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46
Testing for NULL Values
Can test for a NULL value using
IF with backslash.
IF \%1\= =\\ GOTO LABEL
\\==\\
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47
Activity—Using
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
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Activity—Using IF EXIST
to Test for a File
1.
2.
3.
4.
5.
6.
IF \%1\= =\\ GOTO end
IF NOT \%2\= =\\ GOTO next
ECHO You must include a destination name
ECHO for the new directory name.
GOTO end
:next
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Activity—Using 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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Activity—Using 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
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Activity—Using 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.
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Activity—Using 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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62
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
compare
dump
enter
fill
go
hex
input
load
move
name
output
A (Address)
C range address
D (range)
E address (list)
F range list
G [=address] [addresses]
H value1 value2
I port
L [address] [drive] [firstsector] [number]
M range address
N [pathname] [arglist]
O port byte
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Writing Programs to Test
for Key Codes
Summary of command available
within BUG program (p. 576)
proceed
quit
register
search
trace
unassemble
write
P [=address][number]
Q
R [register]
S range list
T [=address] [value]
U [range]
W {address] [drive] [firstsector] [number]
allocate expanded memory
deallocate expanded memory
map expanded memory pages
display expanded memory status
XA [#pages]
XD [handle]
XM [Lpage] [Ppage] [handle]
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:\>DEBUG
-a 100 <Enter>
158E:0100 mov ah,8 <Enter>
158E:0102 int 21 <Enter>
158E:0104 cmp al,0 <Enter>
158E:0106 jnz 10a <Enter>
158E:0108 mov ah,8int21 <Enter>
158E:010A mov ah,4c <Enter>
158E:010C int 21 <Enter>
158E:010E mov ah,8 <Enter>
-r cx <Enter>
CX 0000
:e <Enter>
-n reply.com <Enter>
-w <Enter>
Writing 000E bytes
-q <Enter> <Enter>
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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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Activity—Writing 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.
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The Environment
The operating system stores data in
form of two strings:
 Name of variable
 Value of variable
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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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Activity—Using SET and the
Environmental Variables
KEY CONCEPTS:
 Command processor must be in memory
when keying in command
 Using MORE
 Pressing <Enter> - moves one line at a time
 Pressing <SpaceBar> - goes to end of file
 SET with letter of alphabet - environmental
variables beginning with letter displayed
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Activity—Using 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
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Activity—Using 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
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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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Activity—Using
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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FOR…IN…DO Command
FOR..IN..DO command:
 Allows repetitive processing
 Can be
 issued at the command line
 placed in a batch file
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FOR…IN…DO 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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FOR…IN…DO Command
Syntax at command line:
FOR %variable IN (set) DO
command [command-parameters]
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FOR…IN…DO Command
Syntax in a batch program:
FOR %%variable IN (set) DO
command [command-parameters]
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FOR…IN…DO Command
 GOTO loop is vertical.
 FOR…IN…DO loop is horizontal.
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FOR…IN…DO Command
There is a difference between
a variable and a parameter.
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Activity—Using the
FOR…IN…DO 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
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Activity—Using the
FOR…IN…DO 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:\BATCH>A:\BATCH\ADD A:\BATCH
 Changed dates of files
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More Features of the
FOR…IN…DO Command
New features of FOR…IN…DO 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
FOR…IN…DO Command
New features of FOR…IN…DO command:
 Use tilde operator (~) to:
 Strip a file name of quotation marks
 Expand variable
 Select specific text from ASCII files
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97
Activity—Using Additional
Features of FOR…IN…DO
Command
KEY CONCEPTS:
 Use FOR…IN…DO 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
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Activity—Using Additional
Features of FOR…IN…DO
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
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100
Activity—Using CALL
KEY CONCEPTS:
 Use <Ctrl> + L - to eject a page
 Use <Ctrl> + 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
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Activity—Using 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 <Enter>
Line 2: CD >> A:\BATCH\HOMESAVE.BAT <Enter>
Line 3:CALL HOMNESAVE.BAT <Enter>
Line 4: DEL A:\BATCH\HOMESAVE.BAT <Enter>
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