A remote administration Unix trick

OK, here’s the situation. I had a Linux box running Squid, chugging away, saving us lots of bandwidth and speeding things up and making everything wonderful, but we wanted numbers to prove it, and we liked being able to just check up on it periodically. Minimalist that I am, though, I never installed Telnet or SSH on it. And besides, I haven’t found an SSH client for Windows I really like, and Telnet is horribly insecure.
Sure, I could just walk up to it and log in and look around. But the server was several city blocks away from my base of operations. For a while it was a good excuse to go for a walk and talk to girls, but there weren’t always girls around to talk to, and, well, sometimes I needed to check up on the server while I was in the middle of something else.

So here’s what I did. I used CGI scripts for the commands I wanted. Take this, for example:

echo ‘Content-type: text/html’
echo ”
echo ‘‹pre›’
ps waux
echo ”
cat /proc/meminfo
echo ‘‹/pre›’

Then I dropped those files into my cgi-bin directory and chmodded them to 755. From then on, I could check on my server by typing into a Web browser. Boom, the server would tell me what processes were running, how much memory was in use, and even more cool, how much memory was used by programs and how much was used for caching.

Here’s how it works. The first two lines fake out Apache and your Web browser, essentially just giving them a header so they’ll process the output of these commands. The next line tells it it’s pre-formatted text, so don’t mess with it. This isn’t necessary for all commands, but for commands like ps that output multicolumn stuff, it’s essential. Next, you can type whatever Unix commands you want. Their output will be directed to the Web browser. I echoed a blank line just so the memory usage wouldn’t butt up against the process info. The last line just cleans up.

I wrote up scripts for all the commands I frequently used, so that way when my boss wanted to know how Squiddy was doing, I could tell him. For that matter, he could check it himself.

But if I knew there were going to be girls around, I went ahead and made an excuse to walk that direction anyway. Some things are more important than remote administration, right?

One thought on “A remote administration Unix trick

  • July 24, 2001 at 11:59 pm

    Cool! Just tried your memeory one. Pretty cool trick. What other commands are you using?

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