use strict;
use warnings;

open my $inFH, q{<}, \ <<END or die qq{open: $!\n};
The boy stood on the burning deck,
Eating an ice cream, Walls.
The ice fell down his trouser leg,
And paralysed his left kneecap.
END

while ( <$inFH> )
{
    print qq{$.: $_} if m{([aeiou])\1};
}

close $inFH or die qq{close: $!\n};
[download]

1: The boy stood on the burning deck,
4: And paralysed his left kneecap.
[download]

my feeling is that checking for success on open and close are not needed and could safely be dispensed with. Is this a dangerous assumption?

Cheers,

JohnGG

Update: Thank you, jbert, kyle and Sartan for your responses. As happens, I am very likely to continue checking for success as it is already an ingrained habit and I wasn't even aware that one could open a scalar until recently. jbert, I thought your point regarding possible future implementations was particularly telling.