#do{$data = $data . $_ } while (<DATA>); #gives a uninitialized value 
+in concatenation

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You get the "uninitialized value" warning because the do {...} executes once before a value is being assigned to $_.  Just turn it around: 

my $data;
while (<DATA>) { $data .= $_ }

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BTW, note that $data .= "foo" (or $data = $data . "foo" for that matter) is a special case that does not generate an "uninitialzed value" warning, even if $data is undefined initially: 

$ perl -we 'my $foo; $foo = $foo . "foo"'    # no warning

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while this does, of course: 

$ perl -we 'my $foo; my $bar = $foo . "foo"'
Use of uninitialized value $foo in concatenation (.) or string at -e l
+ine 1.

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In reply to Re: How to use __DATA__ efficiently, help! by Anonyrnous Monk
in thread How to use __DATA__ efficiently, help! by Anonymous Monk

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