On Mar 29, 2021, at 12:50 PM, Rob Pike <robpike@gmail.com> wrote:

Ed is the standard editor.

-rob

On Tue, Mar 30, 2021 at 1:36 AM Larry McVoy <lm@mcvoy.com> wrote:

I had *.clients.your-server.de crawling mcvoy.com in violation of my
robots.txt.  For whatever reason, the tty settings (or something)
made vi not work, I dunno what the deal is, stty -tabs didn't help.

So I had to resort to ed to write and debug the little program below.
It was surprisingly pleasant, it's probably the first time I've used ed
for anything real in at least a decade.  My fingers still know it.

+1 for ed.  It's how many decades old and still useful?


#!/usr/libexec/bitkeeper/bk tclsh

int
main(void)
{
        FILE    log = popen("/var/log/apache2/dns.l", "r");
        string  buf, ip;
        string  dropped{string};

        fconfigure(log, buffering: "line");
        while (buf = <log>) {
                unless (buf =~ /([^ ]+\.your-server\.de\.) /) continue;
                ip = $1;
                if (defined(dropped{ip})) continue;
                dropped{ip} = "yes";
                warn("DROP ${ip}\n");
                system("/sbin/iptables -I INPUT -s ${ip} -j DROP");
        }
}