running php script (php function) in linux bash

First of all check to see if your PHP installation supports CLI. Type: php -v. You can execute PHP from the command line in 2 ways:

1. php yourfile.php
2. php -r 'print("Hello world");'

There are two ways you can do this. One is the one already mentioned, i.e.:

php -f filename.php

The second option is making the script executable (chmod +x filename.php) and adding the following line to the top of your .php file:

#!/path/to/php

I'm not sure though if a webserver likes this, so if you also want to use the .php file in a website, that might not be the best idea. Still, if you're just writing some kind of script, it is easier to type ./path/to/phpfile.php than having to type php -f /path/to/phpfile.php every time.

From the command line, enter this:

php -f filename.php

Make sure that filename.php both includes and executes the function you want to test. Anything you echo out will appear in the console, including errors.

Be wary that often the php.ini for Apache PHP is different from CLI PHP (command line interface).

Reference: https://secure.php.net/manual/en/features.commandline.usage.php

Simply this should do:

php test.php