That would require e.g. seek(), which can be way faster. If the data format allows to use it.

Maybe that's idiom the opener missed (line-by-line reading of input)

while(<>){                # <>: used handle is STDIN
   print if $.==5;        # so $. is that handle's line number
}
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or do it yourself in say $i

my $file="/etc/hosts";
my $i=0; # let's use 1-based numbers
open(FH,"<",$FILE) or die "dying on $FILE";
while(<FH>){
   $i++;
   print "$i: $_" if $i == 5;
}
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