The php.ini file is just a text file and you can use any text editor you like. When I say text editor I do not mean wordpad or a word processor as some of those add extra stuff to the file and can corrupt it.
If you log into DA with your admin account, locate the "File Editor" link and click it. Then click the drop down menu and select "php.ini". Make your changes and then click save.
If you want to use ssh once you are logged in and you su to root, you can do:
Code:
locate php.ini
and find out where the file is on your server. Then go to that directory. ie...