I believe that PHP's filesystem will fit what I want to do but I am having trouble finding the appropiate items to do the following:

-Delete a selected line from a text file (For Example: Remove line 40 of a 100 line text file. Therefore, what was line 41 is now line 40 and there are now 99 lines in total)

-Add a line to a preexisting text file (For Example: A string is added to the end of the file [A 98 line text file becomes 99 line] or a string is inserted at a selected line of in the file[The string is made line 45 and what was previously line 45 becomes line 46])

-Edit/replace a certain line in a preexisting text file (For Example: Line 34 which says "Hello I am sam" is changed to say "This is John")

If any of you know a function or a method that can do either of these, do tell.

You're going to have to read up on fopen (http://us.php.net/manual/en/function.fopen.php) fget and related functions on php.net.

Especially pay attention to contexts if you plan to edit files on a remote server as you have to specify the context in order to open a file for writing across ftp.

Please stop taking up this inobvious sht and use regular database. Some day you will want to sort the data and you WILL have to use db, so why not start using it right now.

But if for some reason you insist on using text files then treat your files as array (by reading them with file()) and use array functions to operate them.