I would like to find out the month from a given date,
how is it possible.

It depends on the format of the given date. Unless we see the format of the date, it is hard to point to one particular solution.

The format of the date is like

Tue Jul 3 06:40:54 EDT 2007

i want to do some manipulation with day, month, year

This is what i am using to process few things

new_day=`date`
month=`echo $new_day | cut -f2 -d ' '`
year=`echo $new_day | cut -f6 -d' '`

now i want to know the which month falls in for the $new_day (1 to 12)

so $new_day is Tue Jul 3 06:40:54 EDT 2007
so how do i find out the month is 07

What OS are you on ? If you have GNU date, then use

date +%b

gives Month Name (Jul)

date +%m

gives Month Number(1-12)

>> date -d "Tue Jul 3 06:40:54 EDT 2007" +%m
works perfectly fine
I am using Linux

Thanks