How to Write. bat batch files

Teaches you how to write. bat batch files

Files with the extension BAT (or CMD in NT/2000/XP/2003) are batch files.

First, the batch processing file is a text file, and each line of this file is a DOS command (most of the time it seems we are prompted in DOS

Command Line), you can use Edit in DOS or notepad in windows and other text file editors.

Allows you to create and modify batch files.

Second, the batch processing file is a simple program that can control the stream running commands through the conditional statement (IF) and flow control statement (goto ).

You can also use the for statement to execute a command cyclically in batches. Of course, the programming capability and C language of batch processing files

Programming statements are very limited and very nonstandard. The Program Statement of batch processing is a line of DOS commands (including internal

And external commands), and the batch processing capability depends mainly on the commands you use.

Third, each written batch processing file is equivalent to a DoS external command. You can put the directory in your dos search path.

Path to make it run anywhere. A good habit is to create a bat or batch directory on the hard disk (for example

C:/batch), and then put all the batch files you have written into this directory, So that you only need to set C:/batch in path, you can

To run all your batch processing programs anywhere.

Fourth, in DOS and Win9x/me systems, the autoexec. bat batch file in the C: root directory runs the batch file automatically.

The file is automatically run at system startup. You can put the command to be run at system startup into this file, such as setting the search path

, Call the mouse driver and disk cache, and set system environment variables. The following is an example of autoexec. Bat running on Windows 98.

Example:
@ Echo off
Path C:/windows; C:/Windows/command; C:/UCDOS; C:/dostools; C:/systools; C:/wintools; C:/batch
LH smartdrv. EXE/x
LH doskey. com/insert
LH ctmouse. exe
Set temp = D:/temp
Set TMP = D:/temp

Functions of Batch Processing
In short, batch processing is used to automatically execute multiple commands continuously.

Here is the simplest application: When the WPS software is started, it must be executed every time (> the previous content indicates the DOS prompt ):
C:/> Cd WPS
C:/WPS> spdos
C:/WPS> py
C:/WPS> wbx
C:/WPS> WPS
If you perform this operation before Using WPS every time, do you think it is very troublesome?

Now, with batch processing, you can simplify these troublesome operations. First, we compile a runwps. bat batch processing file, content

As follows:
@ Echo off
C:
CD/WPS
Spdos
PY
Wbx
WPS
CD/

In the future, every time we enter WPS, we only need to run the runwps batch file.

Common commands

Echo, @, call, pause, and REM (TIPS: Use: replace rem) are the most common commands for batch file processing.

Start from learning.
Echo indicates the characters after this command
Echo off indicates that after this statement, all running commands do not display the command line itself.
@ Is similar to echo off, but it is added at the beginning of each command line, indicating that the command line of this line is not displayed at run time (only the current line can be affected)

).
Call calls another batch file (if you call another batch file directly without calling it

Unable to return the current file and execute subsequent commands of the current file ).
Running pause will pause the execution of batch processing and display the prompt press any key to continue... on the screen, waiting for the user to press

Any key to continue
Rem indicates that the character after this command is interpreted as a line (comment). If it is not executed, it is only used for future reference (equivalent to a comment in the program)

.

Example 1: Use Edit to edit the. BAT file, enter the following content, and save the disk as C:/a. bat. After executing the batch file, you can:

Write all files to a.txt, start UCDOS, and enter WPS and other functions.

The content of the batch file is: Command comment:

@ Echo off does not display subsequent command lines and current command lines
Dir C:/*. *> a.txt: Write the C-drive file into a.txt.
Call C:/UCDOS. Bat call UCDOS
Echo Hello show "hello"
Pause pause and wait for the button to continue
Rem prepare to run WPS Note: Prepare to run WPS
 
 

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2. Teach you how to write. bat batch files
Cd ucdos enters the UCDOS directory
WPS running WPS

Batch File Parameters

The batch file can also use parameters (equivalent to the command line parameters of the doscommand) like C functions, which requires a parameter table

"% ".

% [1-9] indicates a parameter. A parameter is a string separated by spaces (or tabs) after the file name when a batch file is run. Variable availability

From % 0 to % 9, % 0 indicates the Batch Processing Command itself, and other parameter strings are represented in the order of % 1 to % 9.

Example 2: C: the root directory contains a batch of processing files named F. bat with the following content:
@ Echo off
Format % 1

If you execute C:/> f:
When F. bat is executed, % 1 indicates a:, so format % 1 is equivalent to format A:, so the above command is actually executed

Is format:

Example 3: C: the name of the processing file under the root directory is T. bat, and the content is:
@ Echo off
Type % 1
Type % 2

Run C:/> T a.txt B .txt.
% 1: paia.txt
% 2: Invalid B .txt
The following command displays the.txt and B .txt files in sequence.

Special commands

If goto choice for is a relatively advanced command in the batch processing file, if you are very skilled, you are the specialized

Home.

1. If is a condition statement used to determine whether the specified conditions are met and then decide to execute different commands. There are three formats:

1. If [not] "parameter" = "string" command to be executed

If the parameter is equal to the string specified by (not indicates unequal, the same below), the condition is true. Run the command; otherwise, run the next sentence.

Example: If "% 1" = "A" format:

2. If [not] exist [path/] command to be executed in the file name
If a specified file exists, the condition is true. Run the command. Otherwise, run the next sentence.

For example, if exist C:/config. sys Type C:/config. sys
Indicates that if the C:/config. SYS file exists, its content is displayed.

3. If errorlevel <number> command to be executed

Many DOS Programs return a numeric value after running to indicate the result (or status) of the program running. If errorlevel

You can determine the return value of a program and execute different commands based on different return values (the return values must be sorted in ascending order ).

). If the return value is equal to the specified number, the condition is true. Run the command. Otherwise, run the next sentence.

For example, if errorlevel 2 goto X2

2. When the Goto batch processing file runs here, it will jump to the label specified by Goto (label, which is defined by the standard string followed by the label)

In general, the GOTO statement is used together with the if statement to execute different command groups according to different conditions.

For example:

Goto end

: End
Echo this is the end

The label is defined by ": string". The row where the label is located is not executed.

3. Choice uses this command to allow the user to enter a character (for selection) and return different

Errorlevel, and then use if errorlevel to run different commands according to the user's choice.

Note: Choice commands are external commands provided by DOS or windows. the syntax of choice commands of different versions is slightly different. Use

Choice /? View usage.

Choice command syntax (this syntax is the syntax of choice command in Windows 2003, And the syntax of choice in other versions is the same as this

Minor differences ):

Choice [/C choices] [/n] [/CS] [/T timeout/d choice] [/M text]

Description:
This tool allows you to select a project from the selection list and return the index of the selected project.

Parameter List:
/C choices specifies the list of options to be created. The default list is "YN ".

/N hide the Option List at the prompt. The preceding message is displayed,
The option is still enabled.

/CS allows you to select the case sensitivity option. By default, this tool
It is case-insensitive.

/T timeout specifies the number of seconds before the default value is set. The acceptable value is from 0.
Up to 9999. If 0 is specified, there will be no pause. the default option is
Select.

/D choice: Specify the default option after NNNN seconds. The character must be in/C
You must specify the NNNN with/t.
 
 

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3. Teach you how to write. bat batch files
 
/M text specifies the message to be displayed before the prompt. If not specified, the tool only
A prompt is displayed.

/? Displays help messages.

Note:
The errorlevel environment variable is set to the key index selected from the selected set. The first option to be listed
Returns 1, returns 2, and so on. If the key you press is not a valid choice,
The tool generates a warning. If the tool detects an error, it returns the 255
Errorlevel value. If you press Ctrl + break or Ctrl + C, the tool returns 0
The errorlevel value. When the errorlevel parameter is used in a batch program
Sort in sequence.

Example:
Choice /?
For choice/c ync/m ", Press Y, N, or C. "
Choice/T 10/c ync/CS/d y
Select a for choice/c AB/M "option 1 and B for option 2. "
Choice/c AB/N/m "option 1 select a, option 2 select B. "

If I run the command: choice/c ync/M "OK, Press Y, N, or cancel to press C. "
The screen displays:
Press Y to confirm, N to confirm, or C to cancel. [Y, N, C]?


For example, the content of test. bat is as follows (NOTE: When determining the return value using if errorlevel, sort the returned values from high to low ):
@ Echo off
Choice/C dimethyl/M "defrag, mem, end"
If errorlevel 3 goto end
If errorlevel 2 goto mem
If errotlevel 1 goto defrag

: Defrag
C:/DOS/defrag
Goto end

: Mem
Mem
Goto end

: End
Echo good bye

After this batch is run, "defrag, mem, end [d, M, E]?" is displayed. The user can select d m e, and then the if statement is based on the user's choice

Make a judgment. D indicates the program segment whose execution label is defrag, M indicates the program segment whose execution label is MEM, and E indicates the program whose execution label is end.

Segment, each segment finally jumps the program to the end label with the Goto end, the program will display good bye, And the batch processing is completed.

4. The for loop command will execute the same command multiple times as long as the conditions are met.

Syntax:
Execute a specific command on each file in a group of files.

For % variable in (SET) do command [command-parameters]

% Variable specifies a single letter replaceable parameter.
(SET) specifies one or more files. Wildcard characters can be used.
Command specifies the Command executed on each file.
Command-Parameters
Specify parameters or command line switches for specific commands.

For example, a batch file contains one row:
For % C in (*. bat *. txt) do type % C

The command line displays the contents of all files with the bat and TXT extensions in the current directory.

Batch Processing example

1. If-exist

1)

First, use NotePad to create a test1.bat batch file in C:/. The content of the file is as follows:
@ Echo off
If exist/autoexec. bat type/autoexec. bat
If not exist/autoexec. Bat echo/autoexec. bat does not exist

Then run it:
C:/> test1.bat

If the C:/file contains the autoexec. BAT file, its content will be displayed. If it does not exist, the batch processing will prompt you that the file does not exist.

Yes.

2)

Create another test2.bat file with the following content:
@ Echo off
If exist/% 1 type/% 1
If not exist/% 1 echo/% 1 does not exist

Run:
C:/> Test2 autoexec. bat
The command runs the same result as above.

Note:
(1) If exist is used to test whether a file exists. The format is
If exist [path + file name] command
(2) % 1 in the test2.bat file is a parameter. Dos allows passing nine batch parameter information to the batch processing file, which is % 1 ~ % 9 (% 0 indicates Test2

Command itself). This is a bit like the relationship between real parameters and parameters in programming. % 1 is the form parameter, and autoexec. bat is the real parameter.

3) create a file named test3.bat with the following content:
@ Echo off
If "% 1" = "A" Echo Xiao
If "% 2" = "B" Echo Tian
If "% 3" = "C" Echo Xin

If you run:
C:/> test3 A B C
The screen displays:
Xiao
Tian
Xin

If you run:
C:/> test3 A B
Displayed on the screen
 
 

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4. Teach you how to write. bat batch files
Xiao
Tian

During the command execution, DOS will specify an empty string to the parameter % 3.

2. IF-ERRORLEVEL

Create test4.bat with the following content:
@ Echo off
Xcopy C:/autoexec. Bat D: If errorlevel 1 ECHO file copy failed
If errorlevel 0 ECHO, the file is successfully copied.

Then execute the file:
C:/> test4

If the file is successfully copied, the screen displays "successfully copied file"; otherwise, the screen displays "file copy failed ".

If errorlevel is used to test the return value of the previous DOS command. Note that only the return value of the previous command is required.

It must be determined in ascending order.
Therefore, the following batch file is incorrect:
@ Echo off
Xcopy C:/autoexec. Bat D :/
If errorlevel 0 ECHO, the file is successfully copied.
If errorlevel 1 ECHO does not find the copy object
If errorlevel 2 ECHO, the user uses Ctrl-C to stop the copy operation.
If errorlevel 3 Echo preset Error Blocking file copy operation
If errorlevel 4 echo disk write error during copy process

Whether the copy is successful or not, the following:

Copy file not found
You can use ctrl-C to stop the copy operation.
Preset errors prevent file copy operations
An error occurred while writing the disk during the copy process.

Are displayed.

The return values of several common commands and their meanings are as follows:
Backup
0 successfully backed up
1 backup file not found
2. File Sharing conflicts prevent backup from being completed
3. Use Ctrl-C to stop the backup.
4. the backup operation is aborted due to a fatal error.

Diskcomp
0 disks are the same
1 disk is different
2. You can use ctrl-C to stop the comparison operation.
3. The comparison operation is aborted due to a fatal error.
4 preset error abort comparison

Diskcopy
0 disk copy operation successful
1 non-fatal disk read/write error
2. You can use ctrl-C to end the copy operation.
3. the disk copy is aborted due to a fatal processing error.
4. The copy operation is blocked due to a preset error.

Format
0: formatted successfully.
3. Use Ctrl-C to stop formatting.
4. The format is aborted due to a fatal processing error.
5. When "Proceed with format (y/n)?" is displayed )?" End with user input n

Xcopy
0 successfully copied the file
1 copy file not found
2. You can use ctrl-C to stop the copy operation.
4. preset errors prevent file copy operations
5. An error occurred while writing the disk during the copy process.

3. If string1 = string2

Create test5.bat. The file content is as follows:
@ Echo off
If "% 1" = "A" format:

Run:
C:/> test5
Whether to format the: disk is displayed on the screen.

Note: To prevent the parameter from being empty, double quotation marks (or other symbols) are generally used to enclose the string.

.
For example, if [% 1] = [a] Or if % 1 * = *
5. Goto

Create test6.bat. The file content is as follows:
@ Echo off
If exist C:/autoexec. Bat goto _ copy
Goto _ done
: _ Copy
Copy C:/autoexec. Bat D :/
: _ Done
Note:
(1) The colon Before the label is an ASCII character ":", there must be no space between the colon and the label.
(2) The naming rules for labels are the same as those for file names.
(3) DoS supports a maximum of eight characters. When two labels cannot be distinguished, the system redirects to the nearest one.
6.
Create C:/test7.bat. The file content is as follows:
@ Echo off
For % C in (*. bat *. txt *. sys) do type % C
Run:
C:> test7
After the command is executed, all files with the extension bat, txt, and sys in the C: root directory are displayed on the screen (excluding hidden files ).
).