s/^\s+(.*?)\s+$/$1/;   # fails sometimes
s/^\s*(.*?)\s*$/$1/;   # succeeds, but slow
s/^\s*(.*\S)\s*$/$1/;  # fails sometimes
s/^\s*//, s/\s*$//;    # succeeds, but WHY use * ?
s/^\s+//, s/\s+$//;    # succeeds, but is it good?