where can i read up on in regards to skipping blank/empty values when splitting arrays?

Something is wrong wrt your question, since you don't split arrays, you slice or join them. Do you mean omitting empty fields splitting a record, or omitting empty/undefined array elements joining an array?

Sorry I meant, the original file (orders) has blank values in some columns, i'd like for them to be omitted from the results (orders_today.txt) i.e not printed, is that possible?

If you want to filter elements out of an array, use grep (see perlfunc). For example, to keep only strings which have a length of at least 1 character, you could use:

my @strings = split "\t", $line;
my @keep    = grep { length($_) >= 0 } @strings;
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This can be made more concise:

my @keep = grep { length($_) } split "\t", $line;
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Or even:

my @keep = grep length, split "\t", $line;
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perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'