Well, if nothing is printed out it is unlikely that they are the same, notwithstanding appearances. Perhaps there are non-printing characters in one of the strings. You could examine each string character by character, doing it something like this, where to demonstrate I put a NUL in the middle of the string.

$ perl -le '
> $str = qq{ab\0cd};
> print $str;
> print ord for split m{}, $str;'
abcd
97
98
0
99
100
$
[download]

Note that the NUL doesn't show up when the string is printed but can be seen when each character's ordinal value is printed.

I hope this is helpful.

Cheers,

JohnGG