A problem with pattern-matching is synonyms. If the current directory is bin and . denotes the current directory and .. its parent, then bin, ../bin, ../bin/., .././bin/../bin all denote the same directory. If you are trying to block access to the bin directory in a command script, you need to consider all these variants (and an infinite number more). Cite a means by which a pattern matching

algorithm copes with synonyms.

What will be an ideal response?

This
is
the
canonical
form
representation
problem
of
pattern-­?matching.
A
canonical
form
is
a
unique
representation
for
each
item.
A
fully
qualified,
forward-­?directed
path
from
the
directory
root
to
a
node
is
a
canonical
representation
of
the
path.