Version: 0.1
Usage:
        leadingzero CHIPER	
        leadingzero CHIPER END
        leadingzero CHIPER BEGIN END

        leadingzero -h  display this help and exit 

Sample:

$> leadingzero 2
00
01
02
03
04
05
06
07
08
09
10
11
.
.
.
99

$> leadingzero 2 3
00
01
02
03

$> leadingzero 3 3 7
003
004
005
006
007

-------

create direcories from years/1974   to years/2008:
for dic in `leadingzero 4 1974 2008`;do
    mkdir -p ./years/${dic}
done

get the websites from http://samplesite.com/2007/01/ to http://samplesite.com/2007/12/

for month in `leadingzero 2 1 12`;do
    wget http://samplesite.com/2007/${month}/
done