in reply to
Sort an array which contains date formatted elements
snopal beat me to the suggestion of using filesystem data to sort them correctly.
The reason that "it is taking the elements as strings even though i gave it to sort in numerical way" is because the filenames start with text, not numbers. If they were formatted as 7_jul_2007_webadmin.log, then your sort idea would have worked (until 1_aug_webadmin.log, at least - any change of month would break it) but, with the current filename formatting, all of the filenames have a numerical value of 0, so sorting them numerically doesn't do much.