some servers hide them from you. if you have shell access, you can access your site that way, use a utility called putty. it prompts for a username and password, this would be the same if you were signing in through ftp. you navigate with keystrokes rather than the mouse.
cd = change directory
to open a file you can use the nano editor
at the prompt you should be in the directory and see the file named php.ini
at the prompt you will give the command--> nano php.ini
not saying this is the only way, just listing one way.
the way i prefer is to have notepad ++ installed as well as netdrive.
notepad++ is the shiznit when it comes to open sourced editors.
netdrive will create a virtual drive on your local machine and allows you to use notepad++ to edit whatever files are in that virtual drive. i.e. php.ini
you would open it just as if it were located on your local machine, edit it and save it. when you save it, it will save through the virtual drive onto the server. kewl thing is this. it if wacks out, you can do the ol faithful Ctrl + Z to undo the error.
there are many other ways to accomplish this task. i think notepad++ and netdrive are by far the greatest combination of tools available.
cd = change directory
to open a file you can use the nano editor
at the prompt you should be in the directory and see the file named php.ini
at the prompt you will give the command--> nano php.ini
this will open up see more