foreach my $sh (@sh_f) {
    local $/ = ''; # slurp mode
    open IN, '<', $sh    # really? or is it "$cf_dir/$sh" ?
        or die "Can't open '$sh' for input: $!\n";
    open OUT, '>', "$cf_dir/$sh.tmp"
        or die "Can't write '$cf_dir/$sh.tmp': $!\n";

    $_ = <IN>;

    s/^\s*'bgs'\).*?;;//msg;
    s/^(\s*'syslogd'\).*?;;/$1\n$bgs/ms;

    print OUT;

    close OUT or die "Can't close filehandle OUT properly: $!\n";
    rename "$cf_dir/$sh.tmp", $sh; # if appropriate
}