Tibor's Musings

Troubleshooting Mbsync Duplicate UID Errors

I've been using excellent msync tool to synchronise IMAP mailboxes between cloud and laptop. (mbsync seems both faster and less resource-hungry than offlineimap.) Once, probably due to a wrong move operation, the synchronisation started to report "Maildir error: duplicate UID" messages. How to quickly repair this situation?

Here is the …

One Key, Two Functions, or CapsLock as an Escape and Control

In search for greater keyboard ergonomy and improved typing productivity, the CapsLock key seems to be taking place for not much use. Many programmers redefine it to become a modifier key. One popular habit: Vi users prefer to set it to Escape, while Emacs users to Control. What if one …

Accelerating Web Sites with Varnish

Varnish is a popular HTTP accelerator that can speed up web sites. Here is an example of how to set it up on SLC6 box in view of testing CERN Open Data portal responsiveness.

Installation

Official Varnish packages for Scientific Linux 6 (a distribution that is binary API compatible with …

Sending Encrypted Messages with GnuPG

GnuPG is useful to encrypt sensitive information. It can be used in many diverse scenarios, including (1) encrypting sensitive files located on your computer, to be consumed by yourself; (2) encrypting sensitive information to send to your friends via email, to be consumed by others. Here is a detailed recipe …

SLC Kernel OpenAFS Upgrade Enforcement

When running vanilla Scientific Linux CERN distribution, i.e. without Puppet or Quattor to manage the node, then the regular upgrading of the operating system can lead to a kernel dependency problem due to the openafs module. Here is a recipe on how to fix it.

Consider doing a regular …