How can I install PHP 7.4 on Debian 10 (Buster) / Debian 9 (Stretch)?. PHP is the most widely used server-side scripting language in creation of dynamic web pages. PHP applications usually work well with HTML and interact with relation database management systems. With each release of PHP, there are plethora of new features.

This installation of PHP 7.4 on Debian 10 / Debian 9 is available for production use. The GA release was made public on November 28, 2019. It is not recommended to run beta release in Production. It should be used for testing new features in PHP 7.4 and preparation for deprecated features.

Install PHP 7.4 on Debian 10 / Debian 9

Follow the steps covered below to install PHP 7.4 on Debian 10 & Debian 9 Linux distribution. The latest builds of PHP for Debian are available on SURY PHP PPA repository. We’ll add the repository as prerequisite then install PHP 7.4 on Debian 10 / Debian 9 from it.

Step 1: Update system

Ensure your system is updated:

sudo apt update
sudo apt upgrade -y && sudo reboot

Step 2: Add SURY PHP PPA repository

Download and store PPA repository in a file on your Debian Server/Desktop. But first, download GPG key.

sudo apt -y install lsb-release apt-transport-https ca-certificates 
sudo wget -O /etc/apt/trusted.gpg.d/php.gpg https://packages.sury.org/php/apt.gpg

Then add repository.

echo "deb https://packages.sury.org/php/ $(lsb_release -sc) main" | sudo tee /etc/apt/sources.list.d/php.list

Step 3: Install PHP 7.4 on Debian 10 / Debian 9

The last step is to Install PHP 7.4 on Debian 10 / Debian 9. Before installation, update system package list on added repositories.

sudo apt update

Then install  PHP 7.4 on Debian 10 / Debian 9:

sudo apt -y install php7.4

Answer yes when prompted to complete installation of PHP 7.4 on Debian 10 / Debian 9 Linux system.

Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following additional packages will be installed:
  apache2 apache2-bin apache2-data apache2-utils libapache2-mod-php7.4 libapr1 libaprutil1 libaprutil1-dbd-sqlite3 libaprutil1-ldap libbrotli1
  libcurl4 libgdbm-compat4 libgdbm6 libjansson4 libldap-2.4-2 libldap-common liblua5.2-0 libnghttp2-14 libpcre2-8-0 libperl5.28 librtmp1
  libsasl2-2 libsasl2-modules libsasl2-modules-db libsodium23 libssh2-1 perl perl-modules-5.28 php-common php7.4-cli php7.4-common php7.4-json
  php7.4-opcache php7.4-readline psmisc ssl-cert
Suggested packages:
  apache2-doc apache2-suexec-pristine | apache2-suexec-custom www-browser php-pear libsasl2-modules-gssapi-mit | libsasl2-modules-gssapi-heimdal
  libsasl2-modules-ldap libsasl2-modules-otp libsasl2-modules-sql perl-doc libterm-readline-gnu-perl | libterm-readline-perl-perl make
  libb-debug-perl liblocale-codes-perl openssl-blacklist
The following NEW packages will be installed:
  apache2 apache2-bin apache2-data apache2-utils libapache2-mod-php7.4 libapr1 libaprutil1 libaprutil1-dbd-sqlite3 libaprutil1-ldap libbrotli1
  libcurl4 libgdbm-compat4 libgdbm6 libjansson4 libldap-2.4-2 libldap-common liblua5.2-0 libnghttp2-14 libperl5.28 librtmp1 libsasl2-2
  libsasl2-modules libsasl2-modules-db libsodium23 libssh2-1 perl perl-modules-5.28 php-common php7.4 php7.4-cli php7.4-common php7.4-json
  php7.4-opcache php7.4-readline psmisc ssl-cert
The following packages will be upgraded:
  libpcre2-8-0
1 upgraded, 36 newly installed, 0 to remove and 7 not upgraded.
Need to get 15.0 MB of archives.
After this operation, 76.9 MB of additional disk space will be used.
Do you want to continue? [Y/n] y

Use the next command to install additional packages:

sudo apt-get install php7.4-xxx

Example:

sudo apt-get install php7.4-{bcmath,bz2,intl,gd,mbstring,mysql,zip}

PHP configurations related to Apache is stored in /etc/php/7.4/apache2/php.ini

Using PHP with Nginx:

The installation of php on Debian configures Apache. For users interested in running Nginx and PHP, you need to stop and disable Apache service.

sudo systemctl disable --now apache2

Then install fpm extension and nginx packages.

sudo apt-get install nginx php7.4-fpm

PHP FPM configuration files are located in the directory: /etc/php/7.4/fpm/

The nginx and php-fpm services should be running.

$ systemctl status php7.4-fpm nginx
● php7.4-fpm.service - The PHP 7.4 FastCGI Process Manager
   Loaded: loaded (/lib/systemd/system/php7.4-fpm.service; enabled; vendor preset: enabled)
   Active: active (running) since Thu 2019-09-19 17:32:26 UTC; 14s ago
     Docs: man:php-fpm7.4(8)
 Main PID: 12151 (php-fpm7.4)
   Status: "Processes active: 0, idle: 2, Requests: 0, slow: 0, Traffic: 0req/sec"
    Tasks: 3 (limit: 2377)
   Memory: 14.7M
   CGroup: /system.slice/php7.4-fpm.service
           ├─12151 php-fpm: master process (/etc/php/7.4/fpm/php-fpm.conf)
           ├─12152 php-fpm: pool www
           └─12153 php-fpm: pool www

Sep 19 17:32:26 deb10 systemd[1]: Starting The PHP 7.4 FastCGI Process Manager...
Sep 19 17:32:26 deb10 systemd[1]: Started The PHP 7.4 FastCGI Process Manager.

● nginx.service - A high performance web server and a reverse proxy server
   Loaded: loaded (/lib/systemd/system/nginx.service; enabled; vendor preset: enabled)
   Active: active (running) since Thu 2019-09-19 17:32:27 UTC; 12s ago
     Docs: man:nginx(8)
 Main PID: 12362 (nginx)
    Tasks: 2 (limit: 2377)
   Memory: 3.2M
   CGroup: /system.slice/nginx.service
           ├─12362 nginx: master process /usr/sbin/nginx -g daemon on; master_process on;
           └─12363 nginx: worker process

Sep 19 17:32:27 deb10 systemd[1]: Starting A high performance web server and a reverse proxy server...
Sep 19 17:32:27 deb10 systemd[1]: nginx.service: Failed to parse PID from file /run/nginx.pid: Invalid argument
Sep 19 17:32:27 deb10 systemd[1]: Started A high performance web server and a reverse proxy server.

Enjoy your websites and Web Applications development with PHP 7.4 on Debian 10 / Debian 9 Linux system.

Crédits: https://computingforgeeks.com/how-to-install-latest-php-on-debian/

On your system, if you have installed multiple versions of PHP (eg PHP 8.1, 8.0, 7.4, 7.3, 7.2, 7.1 and 5.6). PHP 7.2 is running as default PHP for Apache and CLI. For any requirement, you need to use PHP 5.6. Then you don’t need to remove PHP 7.2. You can simply switch your PHP version to default used for Apache and command line.

We assume you have installed multiple PHP version on your Debian system. Now you need to switch the active PHP version for CLI and Apache2. This tutorial will help you to switch between multiple PHP versions for Apache server and CLI on Debian.

• Read => How to Install PHP on Debian 11 via PPA
• Read => How to Install PHP on Debian 10 via PPA

We have installed PHP 8.1, PHP 7.4 and PHP 5.6 on our Debian system. You can use the same for other PHP versions by changes commands accordingly.

Enable PHP 8.1 as Default Version

You need to set PHP 8.1 as your active PHP version for CLI and Apache2 both. You can do this by disabling Apache2 modules for all other installed PHP versions and configure CLI using the update-alternatives command.

For Apache:-
Run the following command to disable Apache module for other PHP versions.

sudo a2dismod php7.4 php5.6 

Now, enable PHP 8.1 module in Apache server.

• sudo a2enmod php8.1  sudo service apache2 restart 

• For Command Line Interface:-

  sudo update-alternatives --set php /usr/bin/php8.1  sudo update-alternatives --set phar /usr/bin/phar8.1  sudo update-alternatives --set phar.phar /usr/bin/phar.phar8.1  sudo update-alternatives --set phpize /usr/bin/phpize8.1  sudo update-alternatives --set php-config /usr/bin/php-config8.1 

Note – The phpize8.1 and php-config8.1 command is available in php8.1-dev package. This is more useful for compiling PHP modules using pecl.

Enable PHP 7.4 as Default Version

You need to set PHP 7.4 as your active PHP version for CLI and Apache2 both. You can do this by disabling Apache2 modules for all other installed PHP versions and configure CLI using the update-alternatives command.

• Apache:-
  Run the following commands to disable Apache module for other PHP versions

• sudo a2dismod php8.1 php5.6 

  Now, enable PHP 7.4 module in Apache server.

  sudo a2enmod php7.4  sudo service apache2 restart 

• Command Line Interface:-

  sudo update-alternatives --set php /usr/bin/php7.4  sudo update-alternatives --set phar /usr/bin/phar7.4  sudo update-alternatives --set phar.phar /usr/bin/phar.phar7.4  sudo update-alternatives --set phpize /usr/bin/phpize7.4  sudo update-alternatives --set php-config /usr/bin/php-config7.4 

Note – The phpize7.4 and php-config7.4 command is available in php7.4-dev package. This is more useful for compiling PHP modules using pecl.

Enable PHP 5.6 as Default Version

The developers of PHP are no longer supporting PHP 5.6. It is strongly recommended to upgrade to higher PHP version like 7.4 or 8.1. But still you can install and Use php 5.6 on your Debian system if your application required PHP 5.6. Let’s set PHP 5.6 as your default version for CLI and Apache2 both.

• Apache:-
  Run the following commands to disable other PHP versions like (php 8.1, php7.4 etc) for Apache and command line.

  sudo a2dismod php7.4 php8.1 php8.0 

  Now, enable PHP 5.6 module in Apache server.

  sudo a2enmod php5.6  sudo service apache2 restart 

• Command Line:-

  sudo update-alternatives --set php /usr/bin/php5.6  sudo update-alternatives --set phar /usr/bin/phar5.6  sudo update-alternatives --set phar.phar /usr/bin/phar.phar5.6   sudo update-alternatives --set phpize /usr/bin/phpize5.6  sudo update-alternatives --set php-config /usr/bin/php-config5.6 

Note – The phpize5.6 and php-config5.6 command is available in php5.6-dev package. This is more useful for compiling PHP modules using pecl.

Conclusion

In this tutorial, you have learned about switching PHP versions on Debian system. You can change the default PHP version without uninstalling the other versions.

Introduction

Sometimes, the most recent version of an installed package might not work as you expected. Your application may not compatible with the updated package and support only a specific old version of package.

In such cases, you can simply downgrade the problematic package to its earlier working version in no time. Refer our old guides on how to downgrade a package in Ubuntu and its variants here and how to downgrade a package in Arch Linux and its derivatives here.

In some situations, you need not to downgrade the problematic packages. In Linux, we can use multiple versions of the same package at the same time, side by side.

For instance, let us say you are testing a PHP application in LAMP stack deployed in Ubuntu 18.04 LTS. After a while you find out that the application worked fine in PHP 5.6, but not in PHP 7.2 (Ubuntu 18.04 LTS installs PHP 7.x by default).

Are you going to reinstall PHP or the whole LAMP stack again? Not necessary.

You don’t even have to downgrade the PHP to its earlier version. You can simply switch to the previous working PHP version in couple minutes.

1. Switch Between Multiple PHP Versions

Let us check the default installed version of PHP using command:

$ php -v

Sample output:

PHP 7.2.7-0ubuntu0.18.04.2 (cli) (built: Jul 4 2018 16:55:24) ( NTS )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.2.0, Copyright (c) 1998-2018 Zend Technologies
with Zend OPcache v7.2.7-0ubuntu0.18.04.2, Copyright (c) 1999-2018, by Zend Technologies

As you can see, the installed version of PHP is 7.2.7.

After testing your application for couple days, you find out that your application doesn’t support PHP 7.2. In that case, it is a good idea to have both PHP 5.x version and PHP 7.x version, so that you can easily switch between any supported version at any time.

You don’t need to remove PHP 7.x or reinstall LAMP stack. You can use both PHP 5.x and 7.x versions together.

I assume you didn’t uninstall php 5.6 in your system yet. Just in case, you removed it already, you can install it again using a PPA like below.

You can install PHP 5.6 from a PPA:

$ sudo add-apt-repository -y ppa:ondrej/php
$ sudo apt update
$ sudo apt install php5.6

1.1. Switch from PHP 7.x to PHP 5.x

1.1.1 First disable PHP 7.2 module using command:

$ sudo a2dismod php7.2

Sample output:

Module php7.2 disabled.
To activate the new configuration, you need to run:
systemctl restart apache2

1.1.2. Next, enable PHP 5.6 module:

$ sudo a2enmod php5.6

1.1.3 Set PHP 5.6 as default version using command:

$ sudo update-alternatives --set php /usr/bin/php5.6

1.1.4. Alternatively, you can run the following command to set which system wide version of PHP you want to use by default.

$ sudo update-alternatives --config php

1.1.5. Enter the selection number to set it as default version or simply press ENTER to keep the current choice.

1.1.6. If you have installed other PHP extensions, set them as default as well.

$ sudo update-alternatives --set phar /usr/bin/phar5.6

1.1.7. Finally, restart your Apache web server:

$ sudo systemctl restart apache2

Now, check if PHP 5.6 is the default version or not:

$ php -v

Sample output:

PHP 5.6.37-1+ubuntu18.04.1+deb.sury.org+1 (cli) 
Copyright (c) 1997-2016 The PHP Group
Zend Engine v2.6.0, Copyright (c) 1998-2016 Zend Technologies
with Zend OPcache v7.0.6-dev, Copyright (c) 1999-2016, by Zend Technologies

2. Switch from PHP 5.x to PHP 7.x

Likewise, you can switch from PHP 5.x to PHP 7.x version by running the following commands one after another.

$ sudo a2enmod php7.2

$ sudo a2dismod php5.6

$ sudo update-alternatives --set php /usr/bin/php7.2

$ sudo systemctl restart apache2

Crédits: https://ostechnix.com/how-to-switch-between-multiple-php-versions-in-ubuntu/

The network file system NFS is an efficient way of sharing files and directories to other machines in a network. It is based on client-server architecture, where the server directory is mounted onto client systems. NFS allows clients to access shared directories as if they are a part of their own system, and remains a popular way of sharing files among Linux systems.

In this article, we will mount a NFS share on a Debian client machine manually, as well as automatically, upon system boot.

We will use Debian 10 Buster system to run the commands and procedures discussed in this article.

Pre-Requisites

Before proceeding, be sure that:

• NFS server is installed and running on the remote machine
• NFS shared directory on the remote server is exported
• Firewall is allowing access to NFS clients

For the purpose of this article, we have set up two Debian10 machines with the following hostnames and IP addresses:

NFS Server

• Hostname: nfs-serevr
• IP address: 192.168.72.144
• Shared directory: mnt/sharedfolder

NFS Client

• Hostname: nfs-client
• IP address: 192.168.72.145
• Mount point: mnt/client_sharedfolder

Install NFS Client Package on Debian 10 Client Machine

To mount share directories on the client machine, you must first install the NFS client package on it. On the client machine, run the following commands in the Terminal to install the NFS client package:

Step 1: Create a Mount Point for the NFS Server’s Shared Directory

To make the NFS server’s shared directory available to the client, you will need to mount the NFS server’s directory on an empty directory on the client machine.

First, create an empty mount point directory on the client machine. This empty directory will serve as the mount point for the remote shared directories.

We have created the new mount directory “client_sharedfolder” under the /mnt directory using the following command:

Step 2: Mount the NFS Server Shared Directory on the Client

Mount the NFS shared directory to the mount point directory on the client using the following syntax:

Where:

• NFS_IP is the NFS server’s IP address
• NFS_export is the shared directory on the NFS server
• Local_mountpoint is the mount point directory on the client’s system

Based on our setup, we ran the following command:

After mounting the NFS shared directory, you can confirm it using the following command in the Terminal:

Step 3: Test NFS share

Next, test the NFS share on the client machine. To perform a test create some files or directories under the NFS shared directory on the server machine and then access them from the client machine. Follow the procedure below to do this yourself:

1. On the NFS server machine, open the Terminal and use the cd command to navigate to the NFS shared directory:

Next, create some test files:

2. On the NFS client machine, verify whether the same files exist in the local mount point directory.

Note that the mount command does not permanently mount the NFS file system on the mount point. You will have to mount it manually every time you reboot the system. In the next step, we will look at how to automatically mount the NFS file system at boot time.

Mounting an NFS File System Automatically

Automatically mounting an NFS file system saves you the trouble of having to manually mount the file system each time you boot your system. Below is the procedure to do so:

Edit the /etc/fstab file:

Next, add an entry in the /etc/fstab file, as follows:

NFS server:directory mountpoint nfs defaults 0 0

Where:

• NFS server is the IP address of the NFS server
• directory is the shared directory on the NFS server
• mountpoint is the mount point on the NFS client’s machine
• nfs defines the file system type

Based on our setup, we have added the following entry:

After adding the above entry in the /etc/fstab file, save and exit the file by Ctrl + o and Ctrl + x, respectively.

The NFS share will be mounted automatically at the specified mount point the next time you boot your system.

Unmounting an NFS File System

You can easily unmount the NFS shared directory from your system if you no longer need it. To do so, type umount, followed by the name of the mount point, as follows:

Based on our setup, it would be:

Note: The command is “umount,” not unmount (there is no “n” present in the command).

Keep in mind that if you have added the entry in the /etc/fstab file for mounting the NFS, it will be automatically mounted again the next time you boot your system. If you want to prevent it from automatically mounting on the next boot, remove the entry from the /etc/fstab file.

Remember that if the NFS file system is busy, you cannot unmount it, such as if any files are opened on it or you are working on some directory.

There you have it! A simple procedure to mount and unmount the NFS share on the Debian 10 Buster system, both manually and automatically. I hope you liked the article!

Credits to: https://linuxhint.com/mount_nfs_share_debian/