Author Archives: Kenny

Backup Linux Hard driver image

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Linux does not restrict you from copying anything so use TAR to archive all files in one directory. (next time I will try Ghost)

1: Backing-up
sudo su [become a super user]
cd / [ mvoe to the root directory)
tar cvpzf backup.tgz --exclude=/proc --exclude=/lost+found --exclude=/backup.tgz --exclude=/mnt --exclude=/sys /
[c: to create a new archive; v: print verbose info on screen; p:preserve permissions'(to keep the same permissions on everything the same); z for file compress, it might not be a good idea to compress files, use it for non critical applicatons. f: file name]
[make sure you don’t include the file itself, or else you’ll get weird results. You might also not want to include the /mnt folder if you have other partitions mounted there or you’ll end up backing those up too. Also make sure you don’t have anything mounted in /media (i.e. don’t have any cd’s or removable media mounted). Either that or exclude /media.]
[At the end of the process you might get a message along the lines of ‘tar: Error exit delayed from previous errors’ or something, but in most cases you can just ignore that.]

2: Restoring
Make sure you are root and that you and the backup file are in the root of the filesystem.
WARNING: this will overwrite every single file on your partition with the one in the archive!
tar xvpfz backup.tgz -C /

3: Re-create the directories that were excluded:

  • mkdir proc
  • mkdir lost+found
  • mkdir mnt
  • mkdir sys
  • etc…

And when you reboot, everything should be the way it was when you made the backup!

4: GRUB restore
If you installed windows or your GRUB was damaged. then

  1. Pop in the Live CD, boot from it until you reach the Desktop.
  2. Open a terminal window or switch to a tty.
  3. Type “grub”
  4. Type “root (hd0,6)”, or whatever your harddisk + boot partition numbers are (my /boot is at /dev/sda7, which translates to hd0,6 for grub).
  5. Type “setup (hd0)”, ot whatever your harddisk nr is.
  6. Quit grub by typing “quit”.
  7. Reboot.

How to delete a file by using PHP

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Due to some reason I uploaded a plugin called “wpaudio-mp3-player.2.1.0.zip”, which is a light weight mp3 player, to the wordpress /uploads directory. Looks like my web server do not like the word mp3 anywhere in my file name (you have to pay to get around it). so even though I was able to upload it by a program, I can not just delete it by using a command in my FTP client. The only way I can remove this file is to use PHP unlink function.

<?php
$myFile = "wpaudio-mp3-player.2.1.0.zip";
unlink($myFile);
?>

Save this to a php file and upload it to the same directory that I want the file to be deleted. then run this php, I’m done. Apparently php uses similar syntax to the Unix C unlink() function. Everyone thinks there should be a delete command, php.net even has a delete dummy entry only point to the unlink command.

PHP Tutorial -2 (Data type and array)

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PHP tags
<?php ?>
Text Output
echo "something";
Variable
echo "something"; //$ in front, can not begin with a number, case sensitive
Constant
define("name", "value");
Format number
echo sprintf("%01.2f", 25); //25-->25.00
echo number_format(25000, 2); //25000-->25,000.00
Single-quoted Vs double-quoted strings
$age=12; $result1="age"; $result2='age'; //resut1:12 resutl2: $age
Joining string, or concatenation (dot . or .=). To get Hello World!
echo 'Hello'." ".'World';
Format a date ( August 10, 2006 –> 2006/08/10)
echo date("Y/m/d");
Array-Create. index starts with 0, use one of the following ways to create.
$pets[0]="unicorn"
$pets = array("dragon", "unicorn", "tiger");
$pets[] ="dragon"; $pets[] ="unicorn"; $pets[] ="tiger";
$capitals =array("CA" => "Sacramento", "TX" => "Austin", "OR" => "Salem" );
Array-Viewing.
print_r($pets);
var_dump($pets);
Array-Removing.
$pets[2]="";
unset ($pets[4]);
Array-Sorting.
sort("pets"); //To sort an array that has numbers as keys and reassign keys
asort("pets"); //To sort an array that has strings as keys
Array-Getting Values.
list ($firstvar, $secondvar)=$pets;
//To get value from an array that has numbers as keys and put them in variables
extract("pets");
//To copy all the values from an array into variables named from the corresponding keys. The sample from the book is wrong, since no key was assigned in $shirtInfo
current($arrayname) next($arrayname) previous($arrayname) end($arrayname) reset($arrayname);
//Manually iterate through an array
foreach($capitals as $state =>$city)
//walks through the array one value at a time.