How to enable PHP short tags?

Set

short_open_tag=On

in php.ini

And restart your Apache server.

This can be done by enabling short_open_tag in php.ini:

short_open_tag = on

If you don't have access to the php.ini you can try to enable them trough the .htaccess file but it's possible the hosting company disabled this if you are on shared hosting:

php_value short_open_tag 1

For the people thinking that short_open_tags are bad practice as of php 5.4 the <?= ... ?> shorttag will supported everywhere, regardless of the settings so there is no reason not to use them if you can control the settings on the server. Also said in this link: short_open_tag

you need to turn on short_open_tags.

short_open_tag = On

In CentOS 6(tested on Centos 7 too) you can't set short_open_tag in /etc/php.ini for php-fpm. You will have error:

ERROR: [/etc/php.ini:159] unknown entry 'short_open_tag'
ERROR: Unable to include /etc/php.ini from /etc/php-fpm.conf at line 159
ERROR: failed to load configuration file '/etc/php-fpm.conf'
ERROR: FPM initialization failed

You must edit config for your site, which can found in /etc/php-fpm.d/www.conf And write at end of file:

php_value[short_open_tag] =  On

You can follow the following steps:

1-> Go to php.ini file inside /etc/php/7.3/apache2 or inside your PHP version and

2-> Find short_open_tag and set it to On and removing ; from starting.

short_open_tag = On

3-> Restart the server

sudo service apache2 restart

if using xampp, you will notice the php.ini file has twice mentioned short_open_tag . Enable the second one to short_open_tag = On . The first one is commented out and you might be tempted to uncomment and edit it but it is over-ridden by a second short_open_tag

sed -i "s/short_open_tag = .*/short_open_tag = On/" /etc/php/7.2/apache2/php.ini

That works on php7.2 on ubuntu 16, same answer as above by Bradley Flood, although the directory in which the config file is stored has changed.

Also you can change the version in the php string to match your currently installed version.

For docker add this step to Dockerfile

  ARG phpIniPath=/path/to/your/php.ini

  RUN sed -i -e 's/^short_open_tag\s*=.*/short_open_tag = On/' $phpIniPath  

 short_open_tag = On

in php.ini And restart your Apache Server.

I'v Changed the short_open_tag Off to On on my aws centos 7 instance and php7(PHP 7.0.33 (cli) (built: Dec 6 2018 22:30:44) ( NTS )), but its not reflecting the php info page and the code. So I refer may docs and find a solution on my case. Add an extra line after the short_open_tag as asp_tags = On after that restart Apache It works on the code and I go the output correctly

php.ini file

engine = On

; This directive determines whether or not PHP will recognize code between
; <? and ?> tags as PHP source which should be processed as such. It is
; generally recommended that <?php and ?> should be used and that this feature
; should be disabled, as enabling it may result in issues when generating XML
; documents, however this remains supported for backward compatibility reasons.
; Note that this directive does not control the <?= shorthand tag, which can be
; used regardless of this directive. 
; Default Value: On   
; Development Value: Off     
; Production Value: Off  
; http://php.net/short-open-tag

short_open_tag = On

; Allow ASP-style <% %> tags   
; http://php.net/asp-tags
asp_tags = On

Set the asp_tags = On and short_open_tag = On in both the files \apache\Apache2.2.21\bin\php.ini and \bin\php\php5.3.8\php.ini and then restart the apache server.