Your code:

print(split(",", "A,B,C,D")[2]);
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Yields:

syntax error at XXX.pl line YYY, near ")["
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I think what you want is:

print "",(split(",", "A,B,C,D"))[2];
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print can take a file handle as an optional arg and this can be confusing.
putting a dummy null string in front disambiguates this. The split creates a list, put the list into paren and use the bracketed 2 to get C.

Basically don't put a Perl variable or a function call immediately after the keyword "print". Adding more parens is a possible solution, but I prefer the above. Mileage varies.