http://www.perlmonks.org?node_id=547417


in reply to "Err:Use of uninitialized value in string eq" while using split

What's on line 427 of B.out? Maybe something without whitespace (or the end of the file...)?

By the way, split magically ignores leading whitespace and splits on subsequent white spaces if you leave off the pattern or give it a literal space...
@temp1 = split / /, $line1;