help in inserting values in date format

how to assign values in this date format

a=`date +"%H%M%S"`

how to give value of H=22,here in this format so that i can grep 22nd hour.Below is the script
--------------------------------------------------------------------------

a=`date +"%H%M%S"`

for i in *.log
do
cat $i | grep $a | wc -l >> file1.txt
done
-------------------------------------------------------------------------------

actually wat i m doing is greping Particular hour in all the logs files and storing the count in file1.txt

i want a date format that can be flexible enough to input our own hour values,depending upon my requirements.so i need that kind of a format to be used in my script.

Do you mean that you need only the hour field?

date +"%H"

Thanks
Nagarajan G

I'm guessing that you mean something like the following:

#  date +"%H%M%S"
135756

#  date +"22%M%S"
225759

#  hour=23
#  date +"${hour}%M%S"
235809

here is my script
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TZ=`date +%Z`+24 ;a=`date +%Y-%m-%d`

b=`date +"23:%M:%S"`

cd /ednadtu3/u01/pipe/logs
for i in Archiver1.log
do

cat $i | grep $a | grep $b >> /ednadtu3/u01/pipe/naveed/Insert_Date.txt
done
-------------------------------------------------------------------

As this script is outputing the result in Insert_Date.txt but the problem is that file Insert_Date.txt is empty. and i do have results in Acrhiver1.log

as
2008-02-03 23:10:59,345 [Thread-3] INFO -
2008-02-03 23:40:59,660 [Thread-3] INFO -
--------------------------------------------------------------------

not getting why file Insert_Date.txt is empty