php does not show any output

If the php from the linux cli is not showing any output, then most probably it is crashing with a fatal error. It will not show any output if the errors are turned off in /etc/php5/cli/php.ini.

Turn on the errors by setting display_errors = On and you will find out what is causing the problem

Note: If php cli is not working because of a bad configuration, then pear will also not show any output.