Generating dates between two dates

Shell Programming and Scripting
1

HI,
i have row like this

HHH100037440313438961000201001012012073110220002  N

in this i have 2 dates in pos 25-32 and 33-40 , so based upon the se two dates , i need to generated records between these two values
so in the above record 20100101 and 20120731
need to genearte rows like this

HHH100037440313438961000201001012012073110220002  N
HHH100037440313438961000201101012011123110220002  N
HHH100037440313438961000201201012012073110220002  N

pleae advice how to generate this

thanks for your help

2

Just to get the logics right, wouldn't your output's first line second date need to be 20101231?

3

how you are getting 20111231 in row two.
is it last date of previous year of given row always.

4

if the dates are like this 20100101 20120730 , then i need to generate two two rows

20100101 20101231
20110101 20111231
20120101 20120730

5 
awk '
{	p1=substr($0,1,24);
	p2=substr($0,25,4);
	p3=substr($0,29,4);
	p4=substr($0,33,4);
	p5=substr($0,37,4);
	p6=substr($0,40);
	for(i=0;i<=p4-p2;i++)
		{
			d=p2+i;
			if(d==p4)
				{
					p5n=p5
				}
			else
				{
					p5n="1231"
				};
			print p1 d p3 d p5n p6
		}
}'  filename

output is

HHH1000374403134389610002010010120101231110220002  N
HHH1000374403134389610002011010120111231110220002  N
HHH1000374403134389610002012010120120731110220002  N