To install/enable Json support for PHP on a Linux  server, follow the below steps:

1. Install php-pear and gcc

# yum install php-pear gcc

2. Install json module

# pecl install json

3. Now, the json.so file is created under the php lib directory i.e. /usr/lib64/php/modules/ and needs to be called in the json.ini so PHP configuration could read it.

# cd /etc/php.d
# echo "extension=json.so" >> json.ini

4. Once done, restart the httpd service

# /etc/init.d/httpd restart

This is it. However, the other way is to install the php-json module manually. Follow the below steps:

1. Download the json package

# wget http://pecl.php.net/get/json-1.2.0.tgz

or

# pecl download json

2. Untar and goto the newly created directory

# tar -zxf json-1.2.0.tgz
# cd json-1.2.0

3. Create the configuration files and configure json

# phpize
# ./configure

4. Create the installation file and install it

# make
# make install

Once done, json.so will be created in /usr/lib64/php/modules/ directory and needs to be called by the php configuration directory

# cd /etc/php.d
# echo “extension=json.so” >> json.ini

Restart the httpd service and check the php-json module by executing

# php -m | grep json