Your indentation doesn't help see the flow of the code. Reformatted in a more conventional fashion:

sub find_string {
    my ($file, $string) = @_;
    open my $fh, '<', $file;
    while (<$fh>) {
        return 1 if /\Q$string/;
    }
    die "False :Test result is FAIL";

    find_string('search.txt', 'name: abc ');
}
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it is clear that the die prevents the recursive call to find_string.

However, if the file is not huge (say, bigger than a few hundred megabytes), just suck the whole thing into a string and run the regex against it directly:

sub find_string {
    my ($file, $string) = @_;
    open my $fh, '<', $file or die "Can't open '$file': $!\n";
    my $text = do {local $/; <$fh>};

    return $text =~ /\Q$string/;
}
[download]