A Information Tracker (Advanced Counter)

				Ok, so you want to find out who has been visiting your site do you? Well, luckily this is very easy using PERL 5.0! As long as you have CGI support (a cgi-bin) on your web page, and a space for a file (probaly wont be very big unless you experience like 5000 users a day!)
Anyways, lets start off the code with your general declaration...
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#!/usr/local/bin/perl -w

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This will enable PERL on your web page.
Now, what do we want to log? Well, let's log the total amount of visitors, as well as each visitors IP Adress. Then you can compare how many unique visitors you have, plus it is nice and easy.

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$USERIP = $ENV{'REMOTE_ADDR'};

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Ok, that was painless enough. But we want to find out how many total visitors we have had, this is a little more difficult. You must have a file *LOCATED IN YOUR CGI-BIN* called Counter.DAT (for the purpose of this tutorial at least). When you create it make sure the value of the file (the text inside) only is

0

No quotes or anything else, this is just a starting value that lets you add 1 to it each time the user views the page. Now, we need to open this file and get the value (how many views were had before this user came.)

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$fil = "counter.dat";

open(UFILE2, "$fil") || die "Error: Counter File Missing\n";

 $Counterval = <UFILE2>;

close (UFILE2);

$Counterval =+ 1;

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 Ok a little more complicated, but still basically easy. We just opened the file and said whatever was in it can assume the variable $Counterval. So if the file read 5, $Counterval would equal 5. After we got it, we said that it was equal to itself, so again to understand lets patch in 5. 

$Counterval = $Counterval + 1

is equal to

5 = 5 + 1

or 6! It just tells it to add 1 to itself. Ok now lets write it back into the file...
(Note: I am writing, not appending. I want to overwrite the previous variable.)

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open(UFILE3, ">$fil") || die "Error: Counter File Missing!\n";

 print UFILE3 $Counterval;

close (UFILE3);

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Ok. Now we want to save their IP address, so lets create a file called IPLOG.dat. This will hold all our IP's, again to make this tutorial easier, create a file called iplog.dat yourself, but leave it blank. Since we are using the APPEND method, it doesn't have to have a value in it to start out with. Remember, the variable $USERIP was the ip address (look at the top of this tutorial!), so we need to append this into a new line in the iplog.dat file.

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$fil = "iplog.dat";

open(UFILE4, ">>$fil") || die "Error: IPLOG File Missing!\n";

 print UFILE4 "$USERIP\n";

close (UFILE4);

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Great! Lets overview this. First we replaced the old variable $fil with the new file we need to open. Then we opened it and APPENDED (>>) to it with their ip. Notice I used a \n (new line) return at the end, this is to make it alot easier to read, and organize it so that each ip is on one line. Simple enough right? And the user never noticed anything! You can track alot of stuff, that may be useful to your sales, or just cool to know! Anyways, a few tips to remember:


 1) Make sure all files are in the CGI-BIN directory and that your host supports CGI


 2) Make sure that all files are set to CHMOD 755 (Most FTP programs will set this upon request or servers will automatically). If you are unsure, just try the program. If it gives an error then set your CHMOD.


 Anyways, here is the source code without any breaks. Enjoy, its free for grabs, and free for modification! Thanks. - Alex

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#!/usr/local/bin/perl -w

$USERIP = $ENV{'REMOTE_ADDR'};

$fil = "counter.dat";

open(UFILE2, "$fil") || die "Error: Counter File Missing\n";

 $Counterval = <UFILE2>;

close (UFILE2);

$Counterval =+ 1;

open(UFILE3, ">$fil") || die "Error: Counter File Missing!\n";

 print UFILE3 $Counterval;

close (UFILE3);

$fil = "iplog.dat";

open(UFILE4, ">>$fil") || die "Error: IPLOG File Missing!\n";

 print UFILE4 "$USERIP\n";

close (UFILE4);

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Thanks guys, I am just starting with tutorials, I will be doing alot of new ones in CGI (Perl 5) and Visual Basic hopefully. Bye!


UPDATED
I fixed some of the problems I was having with the HTML code, and no you don't *need* to use flock command, only if you have a VERY high traffic site.