Function of shell script programming

The function is actually to give a code a name, each time you use this code can directly use the function name to invoke it.

First, create a function

There are two kinds of formats for creating functions:

Format 1:function function name {

function body

}

Format 2: Function name () {

function body

}

Write function names directly when calling functions.

Second, the use of functions

650) this.width=650; "Style=" border-bottom:0px;border-left:0px;height:auto;vertical-align:middle;border-top:0px; border-right:0px; "title=" 1451877881915477.jpg "alt=" 1.jpg "src=" http://www.178linux.com/ueditor/php/upload/image /20160104/1451877881915477.jpg "/>

In the previous example, a function named test was defined at the beginning and then called directly using the function name.

Third, the return value of the function

1. Execution status return value: The last command state result executed in the function body;

650) this.width=650; "Style=" border-bottom:0px;border-left:0px;height:auto;vertical-align:middle;border-top:0px; border-right:0px; "title=" 1451878220796625.jpg "alt=" 2.jpg "src=" http://www.178linux.com/ueditor/php/upload/image /20160104/1451878220796625.jpg "/>

The function executes successfully and the return value is the default of 0.

2. Custom execution Status return value

You can use the return command to define a status return value that has a range of 0-255 values.

650) this.width=650; "Style=" border-bottom:0px;border-left:0px;height:auto;vertical-align:middle;border-top:0px; border-right:0px; "title=" 1451880709235128.jpg "alt=" 5.jpg "src=" http://www.178linux.com/ueditor/php/upload/image /20160104/1451880709235128.jpg "/>

Iv. functions that accept parameters

The function can also bring in parameters, as shown in the following example:

650) this.width=650; "Style=" border-bottom:0px;border-left:0px;height:auto;vertical-align:middle;border-top:0px; border-right:0px; "title=" 1451888043274715.jpg "alt=" 5.jpg "src=" http://www.178linux.com/ueditor/php/upload/image /20160104/1451888043274715.jpg "/>

Two parameters are referenced in the function, you need to pass the parameters to the past, in the label, when using the function.

650) this.width=650; "Style=" border-bottom:0px;border-left:0px;height:auto;vertical-align:middle;border-top:0px; border-right:0px; "title=" 1451888200350013.jpg "alt=" 6.jpg "src=" http://www.178linux.com/ueditor/php/upload/image /20160104/1451888200350013.jpg "/>

V. Create a function library file

You can save a custom function in a file and call the function you want directly when you need it.

The following is a custom library file:

650) this.width=650; "Style=" border-bottom:0px;border-left:0px;height:auto;vertical-align:middle;border-top:0px; border-right:0px; "title=" 1451889139973661.jpg "alt=" 1.jpg "src=" http://www.178linux.com/ueditor/php/upload/image /20160104/1451889139973661.jpg "/>

Use the functions in this library file in your script:

650) this.width=650; "Style=" border-bottom:0px;border-left:0px;height:auto;vertical-align:middle;border-top:0px; border-right:0px; "title=" 1451889215189359.jpg "alt=" 2.jpg "src=" http://www.178linux.com/ueditor/php/upload/image /20160104/1451889215189359.jpg "/>

Running results of the script:

650) this.width=650; "Style=" border-bottom:0px;border-left:0px;height:auto;vertical-align:middle;border-top:0px; border-right:0px; "title=" 1451889238325861.jpg "alt=" 3.jpg "src=" http://www.178linux.com/ueditor/php/upload/image /20160104/1451889238325861.jpg "/>

You can also use a custom function on the command line, just read the library file when the bash shell starts.

To add a library file to the ~/.BASHRC file:

650) this.width=650; "Style=" border-bottom:0px;border-left:0px;height:auto;vertical-align:middle;border-top:0px; border-right:0px; "title=" 1451889467315974.jpg "alt=" 4.jpg "src=" http://www.178linux.com/ueditor/php/upload/image /20160104/1451889467315974.jpg "/>

To use a custom function directly on the command line:

650) this.width=650; "Style=" border-bottom:0px;border-left:0px;height:auto;vertical-align:middle;border-top:0px; border-right:0px; "title=" 1451889493152704.jpg "alt=" 6.jpg "src=" http://www.178linux.com/ueditor/php/upload/image /20160104/1451889493152704.jpg "/>

Function of shell script programming