How to install php specified functions in linux

When developing web applications using Linux systems, we often need to install PHP and some necessary extensions to achieve our functional requirements. This article will introduce how to install PHP specific function extensions on Linux systems.

1. Introduction to PHP function extension

PHP function extension is a technology that can enhance the features of the PHP language. It allows us to use more built-in functions and extension functions to implement complex functions, such as database operations, image processing, encryption and decryption, etc.

Commonly used PHP function extensions are:

1.1 MySQL extension

This extension provides a set of functions for communicating with the MySQL database. It can connect to the MySQL server and execute SQL queries, and also provides a series of functions to process query results.

1.2 GD library extension

This extension provides a set of functions that can manipulate images in PHP scripts. It can create images, scale, crop, rotate and more. If you want to develop an image processing application like Instagram, then you need to install the GD library extension.

1.3 OpenSSL extension

This extension provides a set of functions that can encrypt, decrypt, sign and verify data in PHP scripts. If you want to develop an online payment platform, you need to install the OpenSSL extension.

2. Installing PHP function extension

Installing PHP function extension is very simple, just use the package manager provided by the Linux system. The following takes installing the MySQL extension as an example to introduce the specific steps.

2.1 Update the package cache

Before installing any packages, we need to update the package cache first. This can be done using the following command:

sudo apt-get update

2.2 Installing the PHP MySQL extension

Installing the PHP MySQL extension is essentially installing the php-mysql package. This operation can be accomplished using the following command:

sudo apt-get install php-mysql

2.3 Turn on the PHP MySQL extension

After installing the extension, we need to turn on the extension in the php.ini file. Use the following command to open the php.ini file:

sudo nano /etc/php/7.2/cli/php.ini

Find the following line and remove the comment to enable the extension:

;extension=mysqli

Change to:

extension=mysqli

Save changes and exit editor.

3. Installation of other function extensions

The installation of other function extensions is very similar, just use the corresponding package name. For example, to install the GD library extension, you can use the following command:

sudo apt-get install php-gd

To enable the extension, you can also modify the php.ini file.

4. Conclusion

Installing PHP function extensions is very easy. We can easily install PHP extensions and enable them by simply using the Linux system's package manager. By installing different extensions, we can complete a variety of functional requirements and make our web applications more powerful and flexible.

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