Crontab: 3- Generate log file

To collect the cron execution execution log in a file :

30 18 * * * rm /home/someuser/tmp/* > /home/someuser/cronlogs/clean_tmp_dir.log

Crontab: 2- file

Crontab syntax :
A crontab file has five fields for specifying day , date and time followed by the command to be run at that interval.

*     *     *   *    *        command to be executed

|     |     |   |    +----- day of week (0 - 6) (Sunday=0) 

|     |     |   +------- month (1 - 12) 

|     |     +--------- day of        month (1 - 31)

|     +----------- hour (0 - 23)

+------------- min (0 - 59) 

Example:

30     18     *     *     *         rm /home/someuser/tmp/*

Crontab: 1- Commands

cron is a unix, solaris utility that allows tasks to be automatically run in the background at regular intervals by the cron daemon.

export EDITOR=vi ;to specify a editor to open crontab file.

crontab -e     Edit your crontab file, or create one if it doesn't already exist.
crontab -l      Display your crontab file.
crontab -r      Remove your crontab file.
crontab -v      Display the last time you edited your crontab file. (This option is only available on a few systems.)

5 Cool PHP Tricks You May Not Know

Over the years I've come across some useful tricks in PHP that are not obvious, but are worth mentioning. This is not meant to be a comprehensive list of all the useful tricks that you can do with PHP.

1. Count Characters in a String

To do this, I've usually just used the function strlen(). However, there is a faster method. Take a look at the following code example:

$string = 'testing';

if(isset($string[6]))
 echo "The string '$string' is at least 7 characters long.";
else
 echo "The string '$string' is less than 7 characters long.";

You treat the $string value like an array by passing an integer value to isset(). If that number plus one is greater than or equal to the number of characters in the string, it will return true. You need to add one because it is zero based.

2. Use PHP Echo like a Function

I've always thought that if you wanted to concatenate strings with echo, you needed to use periods. But you can actually treat echo like a function and use commas instead (it is also faster). Take a look at the following code:

$string1 = 'test-string1';
$string2 = 'test-string2';
$string3 = 'test-string3';

echo 'String #1: ', $string1, '
';
echo 'String #2: ', $string2, '
';
echo 'String #3: ', $string3, '
';

3. Use Single Quotes When Possible

By using single quotes instead of double quotes, you save PHP from having to parse your string for variables. It not only is faster, but I find it more programmer-friendly because it is easier to find variables in your code.

Also, when referencing an array that has a string index, always use single quotes. This prevents PHP from having to figure out exactly what you were trying to say.

4. PHP Variable Variables

There have been several cases when I needed to access a dynamic variable (where the variable name changed). You can do this easily in PHP by using what is called Variable Variables. Take a look at this example:

$var1 = 'nameOfVariable';
$nameOfVariable = 'This is the value I want!!!';

echo $$var1;

5. PHP Output Buffering

I have come across cases where something was being output to the screen that I didn't want (at least at that point, or maybe not at all).

A common example of this is if you have a function or a script that echoes out a string, but you are using the code in that instance where you don't want it to print to the screen at that point (when using a template system or framework system, for example). In this case you would still want to be able to reuse the code, but just prevent anything from being printed out at that exact point.

This will make more sense if you look at this simple example:

ob_start();

echo 'Print to the screen!!!';
$getContent = ob_get_contents();

ob_end_clean();

// Do whatever you want...

// Do something with the printed content (only if you want)...
echo 'Now: ' . $getContent;

Action with Json return

If you need to create an action in Magento with content Json as return, you can use this procedure/code :

        $reponse =  new Varien_Object( );       

        ...

        $reponse->setTimeserver( Mage::getModel('core/locale')->storeTimeStamp(   Mage::app()->getStore() ) );

         ... ... ...

        $this->getResponse()->setBody ( $reponse->toJson() );