How are you populating your @fileData array? Is there any reason not to iterate over the filehandle directly?

use strict;
use warnings;

my $infile = 'whatever';
open my $fh, '<', $infile or die "Couldn't open '$infile' for read: $!
+\n";

while ( my $line = <$fh> ) {
   print "$.\n" if $line =~ m/^1$/;
}
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