Friday, May 16, 2014

List files in sorted order using 'du'

Listing of all the files (and subdirectories) within a directory along with their sizes in sorted and readable format.

$ sudo du /backup/ -h | sort -h

Saturday, December 14, 2013

Find and Replace with Regular Expressions in PHP

If we want to remove a specific part from a string, we can use regular expressions in php

<?php $oldstring="12. What is Your Name";
$newstring=preg_replace('/[\d]+[\.]+[\s?]/', '',$oldstring);
echo $newstring;
?> 


Result : What is Your Name
Here removes serial number from a string. eg : 12. Pattern match search for [\d]+[\.] . This means any digit followed by a dot(.)

Wednesday, August 21, 2013

Age Calculation in MySQL based on Date of Birth Field

To find out age in mysql we can use two methods. (Assume that DOB is the field name in table)

1)SELECT DATE_FORMAT(NOW(), '%Y') - DATE_FORMAT(DOB, '%Y') - (DATE_FORMAT(NOW(), '00-%m-%d') < DATE_FORMAT(DOB, '00-%m-%d')) AS age FROM students


The above query returns the exact age. (looking for birth date)

- 2013-08-22 - 2008-11-02  returns 4 

2) SELECT YEAR( CURDATE( ) ) - YEAR( DOB ) AS age FROM students.

The above query returns the age difference by year (looking for year only)

- 2013-08-22 - 2008-11-02  returns 5

Monday, August 5, 2013

MySQL Command Line Backup

From Shell prompt Enter the following.
 $ mysqldump -u root -pmqr dbname |gzip -9 > /backup/koha/dbname-$(date +"%d-%m-%Y-%H:%M:%S").gz

This command will make mysql backup and compress it in the name format  dbname-06-08-2013-17:17:34.gz

Thursday, August 30, 2012

How to get full URL in PHP


To get full url of running script, we use the following two functions in PHP

  • $_SERVER['HTTP_HOST']
  • $_SERVER['PHP_SELF']

Examples
Consider my url string is : http://mysite.com/products/booking.php

<?php echo $_SERVER['HTTP_HOST']; ?>

Output : mysite.com

echo  $_SERVER['REQUEST_URI'];

Output : /products/booking.php

<?php echo 'http://'.$_SERVER['HTTP_HOST'].dirname($_SERVER['PHP_SELF']);?>

Output : http://mysite.com/products

Thursday, July 19, 2012

Email validation using Regular Expression

Following code shows how to validate email in php.

<?php // chek email validation
if (!preg_match('/^[^0-9][a-zA-Z0-9_]+([.][a-zA-Z0-9_]+)*[@][a-zA-Z0-9_]+([.][a-zA-Z0-9_]+)*[.][a-zA-Z]{2,4}$/',$_POST['email']))
{
echo "invalid Email Address";
}
?>

Detect url contains query string ?

parse_url function is used to break the url components
This function parses a URL and returns an associative array containing any of the various components of the URL that are present.
  • scheme - e.g. http
  • host
  • port
  • user
  • pass
  • path
  • query - after the question mark ?
  • fragment - after the hashmark #


The following code reads url query string and convert into array.

<?php
$queries= parse_url($_SERVER['REQUEST_URI'],PHP_URL_QUERY);

 // splits url query string into array
$queries_elements = split('&', $queries);
//converts to array
for($i = 0; $i != sizeof($queries_elements); $i++)
    {
    $queries = split('=', $queries_elements[$i]);
    //assigns to new array
    $params[$queries[0]]=$queries[1];
    }
var_dump($params);

?> 

More examples 
echo parse_url('http://example.com?mode=edit&id=34', PHP_URL_QUERY);
Output : 'mode=edit&id=34'
echo parse_url('http://example.com?mode=edit&id=34#user', PHP_URL_FRAGMENT)
Output : 'user'
echo parse_url('http://example.com', PHP_URL_SCHEME);
Output : 'http'
echo parse_url('http://example.com?mode=edit&id=34#user', PHP_URL_HOST);
Output : 'example.com'
echo parse_url('http://example.com:88?id=34', PHP_URL_PORT);
Output : 88