Bat Tutorial: section 4 (variable in batch processing)

Bat tutorial:Section 4(Variable in Batch Processing)

Variable in Batch Processing,I divided him into two types:,Are"SystemVariable"And"Custom variables"

System Variables :
Their values are automatically assigned by the system based on predefined conditions. , That is, these variable systems have defined values for them. ,
We don't need to assign a value to him. ,
% Allusersprofile% Returns the "All users" configuration locally. File .
% Appdata % Local return by default Application Program Storage Data .
% CD % Returns the string of the current directory locally.
% Too many line % Local return is used to start the current cmd . EXE Accuracy Command Line.
% Cmdextversion % The system returns the version number of the current "command handler extension.
% Computername % The name of the computer returned by the system.
% Comspec % The system returns the exact path of the executable program of the command line interpreter.
% Date % The system returns the current date. Use and date / T command in the same format. By cmd. EXE generation. Related
For details about the date command, see date.
% Errorlevel % The system returns the error of the previous command. Code . A non-zero value is usually used to indicate an error.
% Homedrive % The system returns the local workstation drive letter that is connected to the user's home directory. Based on the main directory Value Set . Use
The home directory is specified in "local users and groups.
% Homepath % The system returns the complete path of the user's home directory. Set Based on the main directory value. The main directory of the user is
User and group.
% Homeshare % The system returns Network Path. Set Based on the main directory value. The user's main directory is
Specified in "local users and groups.
% Logonserver % Returns the name of the domain controller that verifies the current logon session.
% Number_of_processors % The number of processors installed on the computer.
% OS % System returnOperating System Name. Windows 2000 the operating system of windows _ NT is displayed.
% Path % The system specifies the search path for executable files.
% Pathext % The system returns a list of file extensions that the operating system deems executable.
% Processor_architecture % The chip architecture of the system return processor. Value: x86 or IA64 based
Itanium
% Processor_identfier % The system returns the processor description.
% Processor_level % The system returns the model of the processor installed on the computer.
% Processor_revision % The system returns the version number of the processor.
% Prompt % Return the command prompt settings of the current interpreter locally. By cmd . EXE generation.
% Random % The system returns any decimal number between 0 and 32767. By cmd . EXE generation.
% Systemdrive % Windows server operating is returned. System Root directory (system root directory)
.
% Systemroot % The system returns Windows server operating. System The location of the root directory.
% Temp % And % TMP % The system and the user return the default temporary directory used by the applications available to the current login user.
Some applications require temp, while other applications require TMP.
% Time % The system returns the current time. Use and Time / T command in the same format. By cmd . EXE generation. Related
Time For more information about commands, see time.
% Userdomain % Returns the name of the domain containing the user account.
% Username % Returns the name of the user currently logged on.
% USERPROFILE % Returns the location of the configuration file of the current user.
% Windir % The location of the operating system directory returned by the system.
Such multi-system variables , How do we know what his value is? ?
Input echo in cmd % Windir %
WINDIR variable name ,

For example , For example, you can copy the file to the startup directory of the current account.
Copy D : \ 1 . Bat "% USERPROFILE % \ Start Menu \ Program \ Start \"

% Username % Returns the name of the user currently logged on. Note that directories with spaces must be enclosed in quotation marks.
There are also some System Variables , They mean one thing. ,
They are % 0 % 1 % 2 % 3 % 4 % 5. . . . . . Until % 9. % *
% 0. This is special. , Several layers , First lecture % 1 - % 9. .
% 1. Return the first parameter of the batch processing.
% 2. Return the second parameter of batch processing.
% 3 - % 9 according to this category
Reverse Batch Processing Parameters ? What is the return method? ?
Let's look at this example. , Save the following code as test . BAT and put it on drive C.
@ Echo off
Echo % 1 % 2% 3 % 4
Echo % 1
Echo % 2
Echo % 3
Echo % 4
Go to cmd , Input CD C : \
Enter Test . Bat I am the first parameter I am the second parameter I am the third parameter I am the fourth Parameter
Pay attention to the blank amount in the middle , We will see this result :
I am the first parameter. I am the second parameter. I am the third parameter. I am the fourth parameter.
I am the first parameter
I am the second parameter
I am the third parameter
I am the fourth Parameter
Compare the code , % 1 indicates that I am the first parameter. % 2. I am the second parameter.

These % 1 and % 9. batch processing can also run with Parameters ,
There is another % * What is he? ? He is not very useful , Only return parameters. , However, all parameters are returned at one time.
Value , Do not enter % 1 % 2. Determine
Example
@ Echo off
Echo % *
Save as test . Put bat on drive C
Go to cmd , Input CD C: \
Enter Test . Bat I am the first parameter I am the second parameter I am the third parameter I am the fourth Parameter
We can see that all the parameters are displayed at one time.
Let's start talking about the special one. % 0
% 0. This is not the value of the returned parameter. ,
Meaning of the first layer : Returns the absolute path of the batch processing.
Example :
@ Echo off
Echo % 0
Pause
Save as test . Run bat on the desktop , The following result is displayed.
"C: \ Documents and Settings \ Administrator \ Desktop \ test. Bat"
He printed the path of the current batch processing execution. , This is the absolute path of the returned batch processing.
Level 2 : Execute bat in an infinite loop
Example :
@ Echo off
Net user
% 0
Save as BAT for execution , It will execute the net user command in an infinite loop., Until you manually stop .
The above are some system variables in the batch processing. , There are also some variables , They also represent some features ,
In the for command , For variable already said , No more .
Custom Variables
Hence the name , Custom variables are the variables that we assign to them.
To use custom variables, you must use the set command. , Look at the example .
@ Echo off
Set VaR = I am a value
Echo % VaR %
Pause
Save as BAT for execution , We will see "I am a value"
VaR is the variable name. , = The value to be given to the variable
This is the simplest way to set variables.
If you want to manually enter the variable value , Instead of specifying , You can use the set command/ P Parameter
Example :
@ Echo off
Set / P VaR = Enter the variable value
Echo % VaR %
Pause
VaR variable name = Prompt on the right , Not a variable value