1. while (<>) { ... } or while (my $line = <>) { ... }?
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2. -w or use warnings;?
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3. sub CONSTANT () { ... } or use constant CONSTANT => ...;?
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4. my ($foo, $bar) = @_; or my $foo = shift; my $bar = shift;?
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5. for (@array) { ... } or foreach (@array) { ... }?
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6. print 'foo'; or print('foo');?
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7. 'simple string'; or "simple string"?
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8. glob '*' or <*>?
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9. readline *FOO or ?
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10. for (keys %foo) { $_ and $foo{$_} } or while (my ($key, $value) = each %foo) { $key and $value }?