Depending on the shell you're using, you can use Parameter Expansion. For instance in
Remove matching suffix pattern. The word is expanded to produce
a pattern just as in pathname expansion. If the pattern matches
a trailing portion of the expanded value of parameter, then the
result of the expansion is the expanded value of parameter with
the shortest matching pattern (the ``%'' case) or the longest
matching pattern (the ``%%'' case) deleted. If parameter is @
or *, the pattern removal operation is applied to each posi‐
tional parameter in turn, and the expansion is the resultant
list. If parameter is an array variable subscripted with @ or
*, the pattern removal operation is applied to each member of
the array in turn, and the expansion is the resultant list.
In your case that would mean doing something like this:
Note that the character
# behaves in a similar way on the prefix part of the string.