Reading & editing text files

[esoteric]

Hi guys, im logging activity on my site to text files using;

 

date_default_timezone_set('GMT');
$LogFileLocation = "xxxxxxxx.log";
$fh = fopen($_SERVER['DOCUMENT_ROOT'].$LogFileLocation,'at');
fwrite($fh,date('d.M.Y H:i:s')."\t".$_SERVER['REMOTE_ADDR']."\t".$_SERVER['REQUEST_URI']."\n");
fclose($fh);

 

This is write something like;

[date]  [time]   [ip address] [folder accessed]

 

I then post it like;

<?
$fn = "xxxxxxxxxx.log";
print htmlspecialchars(implode("",file($fn)));
?> 

 

That works fine but what i want to be able to do is read/edit the text files, so the main things i need to add is;

 

The ability to clear the log (using password for confirmation) not sure how to go about this because i don't know how to edit the text file

<input name="password" type="text">

<input type="submit" value="Clear Log?">

 

I also need a script to read the log and alert me an ip address that isn't mine is found, maybe something like

if (an ip that isn't mine == yes)

echo "an unknown ip accessed something"

 

Also lets say i have a script that checks if a name exists, how can i use a text file containing a list of names to be read by a script

if (name exists in text file)

echo "name exists"

else

echo "name doesn't exist"

 

 

All these questions are similar in the fact i need to understand how to open and read text files for specific entries, hope you understand, thanks for any help.