It helps to know that 

while (<FH>) {

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is equivalent to 
while (defined($_ = readline *FH)) {

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and that foreach (LIST) flattens the list it gets. (Well, there are some special cases like foreach (ARRAY) and foreach (RANGE) that are more efficient.)

See the documentation on readline to find out how it behaves differently when used in list context.

In Perl 6, this will not be much of a problem, since it will have "lazy lists". A normal for (LIST) will do what you mean, in an efficient way.

Juerd # { site => 'juerd.nl', plp_site => 'plp.juerd.nl', do_not_use => 'spamtrap' }

In reply to Re: file processing, while and foreach: a n00b experience by Juerd
in thread file processing, while and foreach: a n00b experience by Ryszard

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