In an oversight since corrected, I neglected to mention that the code here was run under Perl version 5.8.9.

I tried 

while (my $line = <DATA>)
{
   print $line;
}

[download]
with my original  __DATA__ both with and without a newline after the 0 on the final line and with strictures and warnings fully enabled and under 5.8.9 and saw no difference in behavior (and no warnings). The reason is easy to see from a deparse: 
c:\@Work\Perl\monks\Marshall>perl -MO=Deparse,-p t_read_DATA_2.pl
use warnings;
use strict 'refs';
print("perl version: $] \n\n");
while (defined((my $line = <DATA>))) {
    do {
        print($line)
    };
}
__DATA__
line the first
second line
penultimate line is line 3
t_read_DATA_2.pl syntax OK
0

[download]
The defined test is automatically added.

Give a man a fish:  <%-{-{-{-<

In reply to Re^6: how do I "initialize" $_ by AnomalousMonk
in thread how do I "initialize" $_ by Anonymous Monk

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