Compress & Extract Linux commands

tar -zcvf archive.tar.gz directory/    => compressing folder
tar -zxvf archive.tar.gz                   => extracting the compressed file

PNG to Jpeg in PHP using GD library

<?php
function png2jpg($originalFile, $outputFile, $quality) {
    $image = imagecreatefrompng($originalFile);
    imagejpeg($image, $outputFile, $quality);
    imagedestroy($image);
}
png2jpg("img/test.png", "img/".time().".jpg", 100);
if ($handle = opendir('img/')) {
	$i=0;
   while (false !== ($entry = readdir($handle))) {
      if ($entry != "." && $entry != "..") {
         echo "<img src='img/$entry' width=150 height=100>    ";
			if($i%10==0 && $i!=0){
				echo "<br>";
			}
			$i++;
      }
   }
   closedir($handle);
}
?>

Multple checkbox selected or not

<script type="text/javascript" src='jquery.js'></script>
<script type="text/javascript">
$(document).ready(function() {
$('#extend_auto_expired').click(function(){
$("input[type=checkbox]:checked").each(function() {
alert( $(this).val() );
});
});
});
</script>
<center>
<form name='ck'>
<?php
for($r=0; $r<10;$r++){
echo "<input type='checkbox' name='t[]' value='$r'>$r<br>";
}
?>
<input type="button" id="extend_auto_expired" value="Extend auto expired" class="buttongreen" name="Submit">
</form>
<center>

How to find disk space in PHP?

<?php
$bytes = disk_total_space(".");
$si_prefix = array( 'B', 'KB', 'MB', 'GB', 'TB', 'EB', 'ZB', 'YB' );
$base = 1024;
$class = min((int)log($bytes , $base) , count($si_prefix) - 1);
//echo $bytes . '<br />';
$total = sprintf('%1.2f' , $bytes / pow($base,$class)) . ' ' . $si_prefix[$class];

$bytes = disk_free_space(".");
$si_prefix = array( 'B', 'KB', 'MB', 'GB', 'TB', 'EB', 'ZB', 'YB' );
$base = 1024;
$class = min((int)log($bytes , $base) , count($si_prefix) - 1);
//echo $bytes . '<br />';
$free = sprintf('%1.2f' , $bytes / pow($base,$class)) . ' ' . $si_prefix[$class];

   $used = (float)$total-(float)$free;
echo "Total Space : $total <br/> Available Space : $free <br/> Used Space : $used ".$si_prefix[$class];
?>

Difference between two dates in PHP

<?php
$date1 = "2015-01-23 00:20";
$date2 = "2015-01-23 05:30";
$seconds = strtotime($date2) - strtotime($date1);
$days    = floor($seconds / 86400);
$hours   = floor(($seconds - ($days * 86400)) / 3600);
$minutes = floor(($seconds - ($days * 86400) - ($hours * 3600))/60);
$seconds = floor(($seconds - ($days * 86400) - ($hours * 3600) - ($minutes*60)));
echo "$days Days, $hours Hrs $minutes mins $seconds sec";
?>

Difference between two dates in Javascript with demo

Enter values in mm/dd/yy hh:mm:ss format
First date and time
Second date and time
Result
In (decimal) hours
In (decimal) minutes
In seconds

Code:
<script type='text/javascript'>

function p (i){

return Math.floor(i / 10) + "" + i % 10;

}

function trunc (i){

var j = Math.round(i * 100);

return Math.floor(j / 100) + (j % 100 > 0 ? "." + p(j % 100) : "");

}

function calculate (form){

var date1 = new Date(form.date1.value);

alert(form.date1.value+"\n\n"+date1)

var date2 = new Date(form.date2.value);

var sec = date2.getTime() - date1.getTime();

if (isNaN(sec)){

alert("Input data is incorrect!");

return;

}

if (sec < 0){

alert("The second date ocurred earlier than the first one!");

return;

}

var second = 1000, minute = 60 * second, hour = 60 * minute, day = 24 * hour;

form.result_h.value = trunc(sec / hour);

form.result_m.value = trunc(sec / minute);

form.result_s.value = trunc(sec / second);

var days = Math.floor(sec / day);

sec -= days * day;

var hours = Math.floor(sec / hour);

sec -= hours * hour;

var minutes = Math.floor(sec / minute);

sec -= minutes * minute;

var seconds = Math.floor(sec / second);

form.result.value = days + " day" + (days != 1 ? "s" : "") + ", " + hours + " hour" + (hours != 1 ? "s" : "") + ", " + minutes + " minute" + (minutes != 1 ? "s" : "") + ", " + seconds + " second" + (seconds != 1 ? "s" : "");

}

</script>

<form id="form">

<table cellpadding="3">

<tr>

<td colspan="2" align="center">Enter values in <font color="#800000">mm/dd/yy hh:mm:ss</font> format</td>

</tr>

<tr>

<td>First date and time</td>

<td><input type="text" name="date1" /></td>

</tr>

<tr>

<td>Second date and time</td>

<td><input type="text" name="date2" /></td>

</tr>

<tr>

<td colspan="2" align="center"><input type="button" name="submit" value="Calculate" onclick="calculate(this.form)" /></td>

</tr>

<tr>

<td>Result</td>

<td colspan="2"><input type="text" name="result" readonly="readonly" size="40" /></td>

</tr>

<tr>

<td>In (decimal) hours</td>

<td colspan="2"><input type="text" name="result_h" readonly="readonly" /></td>

</tr>

<tr>

<td>In (decimal) minutes</td>

<td colspan="2"><input type="text" name="result_m" readonly="readonly" /></td>

</tr>

<tr>

<td>In seconds</td>

<td colspan="2"><input type="text" name="result_s" readonly="readonly" /></td>

</tr>

</table>

Difference between in Mysql & Mango DB