Bitbucket is a paid-for version of Github. Along with Jira and Confluence, it forms the Atlassian framework, a suite of devops tools in widespread use.
Using the Bitbucket web interface, a repository can easily be renamed. However, this causes a change in the URL, which breaks the link from existing clones of the repo. They can be deleted and re-cloned, or renamed. This post explains how to do the rename. Continue reading →
In Perl, hash (associative array) sorting is a common and easy practice. Sorting values by key is easy. And so is sorting by value. But how do you sort the values of a hash by key? One answer is to use a hash slice. Continue reading →
The ESXi embedded host client is a web application served direct from an ESXi server that allows basic management of virtual infrastructure. It is somewhat similar in appearance to Vsphere, though the feature set at the moment is less rich. Vmware has released it as a “fling“, which can be easily added to an existing ESXi server as follows. NB it is recommended to try this in a lab environment rather than a production machine. Continue reading →
The Linux packet filter provides an easy way to protect against unwanted network intrusions. Often referred to simply as “iptables“, it is a basic firewall built into the Linux kernel. Iptables is most useful, perhaps, on those servers most susceptible to attack, such as LAMP systems, content management servers and blogging platforms, especially where they are Internet facing.
Ipset is a fairly recent addition to Linux, having been introduced into kernel version 2.6.32. This means it is supported in Debian 7 and 8, as well as Red Hat 6 onwards. In short, ipset allows a large number of IP addresses to be blocked in an efficient way, as demonstrated below. Continue reading →
Linux disk partition names such as /dev/sda1, /dev/sda2 are not as fixed as they once were. From time to time they can change. Perhaps due to a hardware change or kernel upgrade, or sometimes for no apparent reason. If and when this happens on your system, things can break. In this case, an encrypted swap partition had been configured as “/dev/sda6”, and failed to activate following a change in the the /dev/sdXX partition names. This article describes the symptoms and a fix.
The article also discusses a bug affecting Ubuntu 14.04 based distributions, which can make it more difficult to recover an encrypted swap configuration broken by a device name change. Continue reading →
This article presents a few informal benchmarks comparing the Raspberry Pi to the Raspberry Pi 2. The original Pi has a single core ARM v6 processor. The Pi 2 is quad core, ARM v7, and clocked faster than the Pi 1. But is it really six times as fast, as the makers claim ? Short answer: yes it is. And then some. Continue reading →
Here is a tip for speeding up WordPress, especially if you are running it on a low power server. I made the change to WordPress running on a small ARM server, resulting in an immediate and dramatic speed up. It works because it prevents bots on the Internet from wasting your server resources. Continue reading →
This article discusses some of the caption and border effects available with the ImageMagick image processing package. ImageMagick is freely available for Linux and Windows. It offers a huge number of image processing options, so many in fact, that using the program can be a little tricky.
The following examples were evolved from the ImageMagick online documentation, plus a good deal of trial and error to get the details right. I used Linux, but the same commands should work under Windows. Continue reading →
Solaris administrators may have seen the message “Catastrophic file error – zero length” in their system logs. Although it sounds serious, there is nothing “catastrophic” about it. This post explains how to stop the message from flooding your log files. Continue reading →