This looks like a failed merge attempt. If you look at the blocks between ===, you will find that both variables are declared twice, but with different value for $oldVersion.

For an explanation of what Perl sees, see the Perl Documentation on Quotes and Quote-like Operators. But you don't seem to want a here-document there - the << and === and >>> are the remains of a failed/untested merge.

You appear to be using a content revisioning system, attempted to merge two branches, and a conflict arose.

Imagine the following scenario:

Change Joe made         Original file           Change Jane made

...                     ...                     ...
my $newVersion = '1';   my $newVersion = '1';   my $newVersion = '1';
my $oldVersion = "2";   my $oldVersion = "1";   my $oldVersion = "3";
...                     ...                     ...
[download]

The merge tool cannot safely merge those, so it produced the text you're asking about and expects you to resolve the conflict manually.

You seem to use SVN for version control system. This happens when you checkout some code, modify it and before you commit it someone else commits the same file. If SVN fails to merge your and someone else's code it leaves different versions of files in the directory where you checked out the code (e.g. script.pl.mine, script.pl.r914 etc.)

When it happens with me I just remove all the versions of the file (script.*) having different extensions, check out the code again, merge my changes in the updated file and commit it before someone else do it again. :-)