First off, a zombie process isn’t really a process. At least it’s not executing anymore. A zombie process is more of a “state”, and that state is “defunct”. However, we typically refer to them as “zombie processes”, so I’ll stick with convention here. Second, a zombie process on a Unix system is a child process [...]
UPDATE (May 06, 2012): I apologize for mentioning it supports encryption. Pool version 28 is the latest source that the Free Software community has. Encryption was not added until pool version 30. So, encryption is not supported natively with the ZFS on Linux project. However, you can use LUKS containers underneath, or you can use [...]
Just recently, I needed to mount a KVM raw image file, because it was depending on a network mount that was no longer accessible, and any attempts to interact with the boot process failed. So, rather than booting off a live CD, or some other medium, I decided to mount the raw image file. After [...]
If you’re not using NetworkManager or Wicd, or some other similar tool to automatically manage your network interfaces for you, this post is for you. In the Debian world, you have a single file that manages your network interfaces. It can manage VLANs, bonded interfaces, virtual interfaces and more. You can establish rules on what [...]
I’ve seen on the internet, and elsewhere, that when there are too many arguments for rm(1) to handle, that the following command will suffice: % find /path -exec rm -rf {} \; While certainly functional, it’s not optimal. If there are thousands of files (as is often the case at my job), this command is [...]
I created a Debian package for Salt, doing my best to adhere to the Debian Policy. You can find it at http://mentors.debian.net/package/salt. If you’re not familiar with Salt, head over to http://saltstack.org and check it out. From the author’s website: Salt is a powerful remote execution manager that can be used to administer servers in [...]
Too often, I see the recommendation on forums, IRC, and elsewhere across the internet to use improper tools for creating ISO images. For example, consider the following two commands, both of which are not the correct way to build a CD/DVD image: $ dd if=/dev/scd0 of=cdimage.iso # NO! Or worse yet: $ cat /dev/scd0 > [...]
This post comes from BashFAQ/081 on Greg’s Wiki. He argues why you should not be using which(1) to determine if a command is in your $PATH at the end of the page. I’ll put that argument at the front: The command which(1) (which is often a csh script, although sometimes a compiled binary) is not [...]
I have chosen the path of system administration for my career. It’s been very rewarding, and I really love my job. However, there are times when I make stupid mistakes that cost others money. I’m sure we’ve all been there. It’s stressful, embarrassing and can really shake you up, if you mistake is bad enough. [...]
Recently, I’ve made the switch from GNU Screen to Tmux for my remote terminal multiplexor. I still prefer GNU Screen for serial connections, however (something the Tmux developers don’t seem to think is important). So, when getting it setup, I wanted my hardstatus line to imitate my GNU Screen hardstatus line as closely as possible. [...]
I will be attending the Ohio Linux Fest this September (in about two weeks) giving a talk on “Password Theory and Breaking Encrypted Filesystems”. The talk covers some theory on what exactly makes a “secure password”, including some mathematics, entropy, random number generators, shadowed passwords, salts, rainbow tables and cryptographic hashes. I end the talk [...]
This post comes from Matt Taggart, who put together a document about the best practices for using OpenSSH. A lot of the points brought up in that document rang the bells of common sense, and are so good, it’s worth blogging about in hopes that the points mentioned therein reach as many as possible. I’ve [...]
This post is a quickie to see what the current generation is like these days. I’m an old fart (not as old as many reading this post), but I remember when 5 1/4″ floppy drives were “standard”, and 3 1/2″ were the new fad. Then came Iomega Jazz drives, and the like. CDRW hit the [...]
Quick post, outlining what I think makes the Unix family of operating systems superior, including “unix-like” operating systems such as GNU/Linux, BSD, and others. Of course, the list isn’t exhaustive- it’s just something I threw together in 10 minutes. The motivation of the post was a discussion in ##unix on Freenode. The command line interface. [...]
I’ve been tasked at work with shredding drives. Not physically, mind you, but digitally. Usually, I grab a copy of the latest version of Knoppix, boot up, pull up a terminal, and grab GNU Shred. Something like: shred -n 3 -v /dev/sda It works well enough. However, it doesn’t display a real useful progress meter, [...]
