I wanted to install Symfony on Mac OS X Lion. Apparently, as MAMP was already installed on my computer, there was a problem with the "timezone" field in the php.ini file. I can't remember exactly the error but basically, Symfony installation required a timezone like "Europe/Paris" but MAMP apparently changed that part.

Well, it's very vague but I've seen on the web that other people had the same issue. So I tried one of the solution I found (without success) but:

1. It didn't work.
2. I can not use the php command anymore ("-bash: php: command not found"). I can not remember the exact commands I did to go back.

Here are some potential relevant commands I found in my history and that correspond with the beginning of my problem, in this order:

sudo mv /usr/bin/php /usr/bin/php-old
sudo ln -s /Applications/MAMP/bin/php5/bin/php /usr/bin/php
rm /usr/bin/php-old
sudo cp php.ini.default /etc/php.ini
rm php.ini but I don't know anymor in which repertory I was. 
sudo mv /usr/bin/php-old /usr/bin/php