Shell Programming and Scripting

If I have a filename as
filename.txt.20090807
and I use
for FILE in `find . -name "filename*" -type f`
do
my_time=${FILE#./filename.txt.}
I get my output as 20090807
However if my filename is
filename.Y20090807.txt
Is there a way I can use metacharacters in my variable
my_time=${FILE#./filename.????????????????????}
to get the date 20090807

Code:

> echo filename.Y20090807.txt
filename.Y20090807.txt

> echo filename.Y20090807.txt | tr -d "[:alpha:]"
.20090807.

> echo filename.Y20090807.txt | tr -d "[:alpha:]" | tr -d "[:punct:]"
20090807

Can i use your code inside my variable

my_time=${FILE#./filename.txt.}

or else my loop wont work

Code:

> mytime=`echo filename.Y20090807.txt | tr -d "[:alpha:]" | tr -d "[:punct:]"`

and then to verify that I stored correctly into the variable

Code:

> echo $mytime
20090807