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📜  批处理脚本-功能

📅  最后修改于: 2020-11-22 17:51:19             🧑  作者: Mango

函数是一起组织以执行特定任务的一组语句。在批处理脚本中，采用了类似的方法将逻辑语句组合在一起以形成一个函数。

像其他任何语言一样，批处理脚本中的函数遵循相同的过程-

  • 函数声明-它告诉编译器函数的名称，返回类型和参数。

  • 功能定义-它提供了函数的实际身体。

功能定义

在批处理脚本中，通过使用label语句定义函数。重新定义一个函数，它可以将一个或多个值作为函数的输入“参数”，在主体中处理函数，然后将这些值作为输出“返回类型”传递回函数。

每个函数都有一个函数名称，该名称描述了该函数执行的任务。要使用一个函数，您要“调用”该函数的名称并传递与该函数的参数类型匹配的输入值(称为自变量)。

以下是一个简单函数的语法。

:function_name 
Do_something 
EXIT /B 0

  • 该函数名是给它应该有一定的意义，内容相匹配的函数实际执行函数的名称。

  • EXIT语句用于确保函数正确退出。

以下是一个简单函数的示例。

例

:Display 
SET /A index=2 
echo The value of index is %index% 
EXIT /B 0
S.No Functions & Description
1 Calling a Function

A function is called in Batch Script by using the call command.
2 Functions with Parameters

Functions can work with parameters by simply passing them when a call is made to the function.
3 Functions with Return Values

Functions can work with return values by simply passing variables names
4 Local Variables in Functions

Local variables in functions can be used to avoid name conflicts and keep variable changes local to the function.
5 Recursive Functions

The ability to completely encapsulate the body of a function by keeping variable changes local to the function and invisible to the caller.
6 File I/O

In Batch Script, it is possible to perform the normal file I/O operations that would be expected in any programming language.
7 Creating Files

The creation of a new file is done with the help of the redirection filter >. This filter can be used to redirect any output to a file.
8 Writing to Files

Content writing to files is also done with the help of the redirection filter >. This filter can be used to redirect any output to a file.
9 Appending to Files

Content writing to files is also done with the help of the double redirection filter >>. This filter can be used to append any output to a file.
10 Reading from Files

Reading of files in a batch script is done via using the FOR loop command to go through each line which is defined in the file that needs to be read.
11 Deleting Files

For deleting files, Batch Script provides the DEL command.
12 Renaming Files

For renaming files, Batch Script provides the REN or RENAME command.
13 Moving Files

For moving files, Batch Script provides the MOVE command.
14 Batch Files – Pipes

The pipe operator (|) takes the output (by default, STDOUT) of one command and directs it into the input (by default, STDIN) of another command.
15 Batch Files – Inputs

When a batch file is run, it gives you the option to pass in command line parameters which can then be read within the program for further processing.
16 Using the SHIFT Operator

One of the limitations of command line arguments is that it can accept only arguments till %9. Let’s take an example of this limitation.
17 Folders

In Batch Script, it is possible to perform the normal folder based operations that would be expected in any programming language.
18 Creating Folders

The creation of a folder is done with the assistance of the MD (Make directory) command.
19 Listing Folder Contents

The listing of folder contents can be done with the dir command. This command allows you to see the available files and directories in the current directory.
20 Deleting Folders

For deleting folders, Batch Scripting provides the DEL command.
21 Renaming Folders

For renaming folders, Batch Script provides the REN or RENAME command.
22 Moving Folders

For moving folders, Batch Script provides the MOVE command.