As a special case, specifying a PATTERN of space (' ') will
split on white space just as "split" with no arguments does.
Thus, "split(' ')" can be used to emulate awk's default 
behavior, whereas "split(/ /)" will give you as many null initial
fields as there are leading spaces.  A "split" on "/\s+/" is
like a "split(' ')" except that any leading whitespace produces
a null first field.  A "split" with no arguments really does a
"split(' ', $_)" internally.
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