How to Use a Query String in Perl

A query string is the part of a URL which is attached to the end, after the file name. It begins with a question mark and usually includes information in pairs. The format is parameter=value, as in the following example:

www.mediacollege.com/cgi-bin/myscript.cgi?topic=intro

Query strings can contain multiple sets of parameters, separated by an ampersand (&) like so:

www.mediacollege.com/cgi-bin/myscript.cgi?topic=intro&heading=1

The idea is that the information contained in the query string can be accessed and interpreted by a script. Specifically, the query string data is contained in the variable $ENV{'QUERY_STRING'}.
To Access the Query String Data

You can use a block of code like the one below to access and organise the query string:

if (length ($ENV{'QUERY_STRING'}) > 0){
$buffer = $ENV{'QUERY_STRING'};
@pairs = split(/&/, $buffer);
foreach $pair (@pairs){
($name, $value) = split(/=/, $pair);
$value =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C", hex($1))/eg;
$in{$name} = $value;
}
}

This code will create a hash called $in, from which you can call specific variables like so:

$topic = $in{'topic'};
$heading = $in{'heading'};

Sample code:
#!/usr/bin/perl

# Whether the method used is GET or POST, store the parameters passed in $QueryString
if($ENV{'REQUEST_METHOD'} eq "POST") {
read(STDIN, $QueryString, $ENV{'CONTENT_LENGTH'});
} else {
$type = "display_form";
$QueryString = $ENV{QUERY_STRING};
}

# split the QueryString at &'s to give you a list with each element with a format like "name=value"
@NameValuePairs = split (/&/, $QueryString);

# Split each NameValue pair, replace +'s by spaces, get the character equivalent of any data in hex (%XX) and finally, store it in an associative array
foreach $NameValue (@NameValuePairs) {
($Name, $Value) = split (/=/, $NameValue);
$Value =~ tr/+/ /;
$Value =~ s/%([\dA-Fa-f][\dA-Fa-f])/ pack ("C",hex ($1))/eg;
$in{$Name} = $Value;
$color =$in{'color'};
$name =$in{'name'};
}

print "Content-type: text/html", "\n\n";
HTML CODE HERE

Linux Remote Desktop For Controlling Windows XP / Vista / Server 2003 ( rdesktop )

Connect to MS Windows 2000/2003 server from Linux, type the following command at a shell prompt (connect to Windows server called mw2sn100.mycorp.com)

$ rdesktop mw2sn100.mycorp.com

Or connect to windows XP/Vista workstation having IP 192.168.1.17:

$ rdesktop -a 24 -r sound:remote pg-svelayut &

Remote windows XP desktop

Please note that you must first enable remote desktop connection under Windows Server/XP.

* Go to Windows XP Desktop
* Right Click on My Computer
* Select properties
* Select Remote tab
* Enable Remote desktop.
* Save the changes.

Make sure enterprise firewall allows incoming connection on TCP port 3389. rdesktop supports many other options, see man page of rdesktop or visit main website of rdesktop for more information.

Map Linux nfs drive from DOS

How to map a drive using command prompt

First click on Start and then Run. Type cmd in the Open box.

Then type the following DOS command to map the network drive:

net use x: \\computer name\share name

where x: is the drive letter you want to assign to the shared folder.

You can delete a mapped network drive using the command prompt by typing in

net use x: /delete