See split. Your message (a warning, not an error, IIRC) reflects split's dis-inclination to let you split to a scalar ($list). You'll also want to read chomp for how to get those newlines out of your way.

Suggest you start with something like the following, which (sorta') follows your scheme:

my @list;
for my $item(@array1) { # assumes you are reading the list into an arr
+ay and also
                        # assumes that the command between c1 and the 
+newline is spurious
    push @list, $item;
}
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Then write code to process @list, pushing its elements onto @w,@x,@y,@z.

Use the docs. As a guru once remarked, "You can't just make stuff up and expect the computer to understand."

Update: typos fixed (in just 3 tries); clarification about the "error" in the 1st para.