for example:

i hav a string like :

/rmsprd/arch01/rmsprd/rmsprdarch72736.log

how I can extract

my_num=72736?

I know I can

echo "/rmsprd/arch01/rmsprd/rmsprdarch72736.log" | tr "/" " " | awk '{ print $4 }' to get rmsprdarch72736.log