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Author: halfgaar

Halfgaar is Wiebe. Wiebe is a contributing author on this weblog. He also has a lot of stuff (such as long, in-depth articles) on his personal website.

Wiebe works at YTEC, where he is a senior developer of customer-specific tailor-made software (“klantspecifieke maatwerk software“) for clients in a few select markets: wholesale, printing and healthcare.

Creating a bash fork bomb

Logged into a Unix machine? Does "ulimit -a" say that the max number of user processes is unlimited? Then type the following to crash the machine (provided it uses bash, or another shell with compatible syntax): Read More »

Setting up a domaincontroller with Samba

I occasionally have to set up a domain controller using Samba. There are a lot of guides and howto's available, but I made a step-by-step howto just for myself, and I thought it'd be smart to make it available on the internet for me to access anywhere. Read More »

Playing Quake3 in Linux with Skype or Teamspeak

I wanted to play a game of Quake3 against someone, and have Skype or Teamspeak open at the same time, for obvious reasons. Somehow, it reported the sound device being in use: "device or resource busy". This doesn't make any sense, because my card can do hardware mixing, and also because all other games work fine with Skype or Teamspeak active. Read More »

Mounting partititions residing inside a disk image

When you've read a disk with dd or ddrescue into an image file, one of the things you want to do is mount the partitions inside it. But, how does one do that? The answer is using losetup, with a bit of knowledge of partition offsets. Read More »

Rolling back a failed rdiff-backup session on a full partition

For those of you who use rdiff-backup, you may have run into the situation where the partition you're backing up to has no more space available. This is a very annoying situation, because rdiff-backup needs space to be able to roll back the session, so you're kind of stuck. You might think: "doesn't a decent file system have a reserved amount of space for the super user?" Yes, decent file systems do, but you'll often be running rdiff-backup as root, so that won't do any good. Read More »

Getting your terminal unstuck

Have you ever had your terminal freezing on you for a reason you can't identify? Fret no more, because this post will save your future login session. Read More »

Efficient scanning and storing of documents

I don't like having an administration in dead-tree format, but there are those who insist on sending you all kinds of things in this format. To make this data easier to access and back up, I scan it to a digital format. I used to do this manually, with the GIMP, but I decided it was time for some automation. Therefore I wrote a script, which scans whatever you put under the lid of the scanner in lineart mode, and stores it very efficiently in a DjVu DjVuBitonal document. And here it is: Read More »