This has two parts.

First, sudo, which ubuntu encourages using rather than su. Sudo can be set up to allow users to do just some things as root rather than everything, by editing the file /etc/sudoers.

Second, various Ubuntu programs that run as root. Some expect that the user's $PATH starts with /sbin and /usr/sbin, and run programs without specifying the complete file name.

If a user has limited sudoers privileges, then various Ubuntu-supplied programs can often be tricked into granting the user complete root access.

For example, sudo apt-get install foo will often run ldconfig, start-stop-daemon and more. Not always, but often enough to make it a FAQ.

I feel sure that whoever reports this will be told by the sudoers maintainers that the problem is with e.g. apt-get, and by the apt-get people that the problem is with sudoers. Both are reasonable responses, but I'd rather write code than argue. So all I'll do is publish this.

I've wanted more RAM and a third monitor for a while. Upgrade time. I hate upgrading hardware, it's the worst of chores.

The new hardware is a Zotac Fusion ITX A motherboard including a Radeon 6310 graphics blah, a passive Radeon HD5450 graphics card (actually a 5430 chip), and the rest is from from the previous libertango: (more…)

Computers are good. More computers are better. But more keyboards are not. Swapping keyboards all the time was how I first ruined my wrists, almost twenty years ago.

That's why now, with a Mac Mini under and a linux box near my working desk, I definitely don't want to use two keyboards. One is the right number, and Synergy is the way to share keyboard and mouse. (more…)

Mikrotik RouterOS doesn't have a tcpdump command. It has solutions for most/all of the problems I like to solve with tcpdump, though. (more…)

What Amazon wrote:

We have noticed that one or more of your instances are running on a host degraded due to hardware failure. [...]

The host needs to undergo maintenance and will be taken down [...]

What Amazon might have written:

Thought you were clever, eh? Running that fancy Cassandra cluster? I bet you didn't expect your redundant copies on several Cassandra nodes to really be stored on the same crummy drive. (more…)

We have two access points at home, and wireless clients can roam freely, keeping their IP address.

Most clients can. Android phones and tables could not. For example, if a Motorola Xoom (Android 3.0) was in range of both APs, then it would switch to the other AP every 3-4 seconds.

The problem was that one AP was set to support only 802.11g, while the other was set to support b/g. Setting both to G-only solved the problem. The Xoom now connects quickly and keeps its connection (so long as it remains still at least).

After a few years of service, my ReadyNAS NV+ broke one day. The hardware was fine, but the software had painted itself into a corner and didn't want to boot at all.

Googling showed that lots of other people have been bitten by the same bug. I phoned support. The support person told me that my box was out of warranty, and would I please post to a web forum and I'm sure someone will help you. I could tell from his voice that he didn't really believe that.

I eventually moved the drives to a linux box. LVM (on ubuntu 10.04) recognised the drives automagically and ext3 let me mount the file system, so I bought a new Synology NAS and copied the data to it.

When I did a factory reinstallation (the hard way) the ReadyNAS booted without problems. From now on I'll use it to back up other devices, nothing more.

It's debian. apt-get install works. But they removed some files without telling dpkg, and edited some, too.

For example, they removed the man pages. Why? It's a NAS: Disk is the one resource it has in abundance, and the man pages aren't even big.

Foo.