If you store application data in memcache, you may want to invalidate it once you deploy a new version to avoid corruption or weird results. There are several ways to do this but I recently tried one using nothing but BASH, and I like it.

Recently I needed ogg123 on an Ubuntu server to convert some media. Naturally, I wanted to use aptitude to install it, but I didn't know what package it was in. Now, you can always google of course, but you can also use system commands to find the package you need.

Synchronizing files from one server to another is quite awesome. You can use it for backups, for keeping web servers in sync, and much more. It's fast and it doesn't take up as much bandwidth as normal copying would. And the best thing is, it can be done with only 1 command. Welcome to the wonderful world of rsync.

It's always a good idea to backup important data. Your files and settings can easily be archived. But how can you backup & restore all applications that you've installed over the last couple of years? Here's an easy trick that works for both desktops & servers, and that can also be used to synchronize installed packages in a web cluster, making all the servers run the same software.

CDs and DVDs don't have the eternal life, so you might want to back them up as ISO images. All the files and properties of the original disc, stored in a single file. You can also create ISO images and store them on your network for easy distribution of software installations. Here's how to create and mount ISO images on Linux.

Making sure your system is up to date is a key attribute to it's security. Furthermore Ubuntu releases updates pretty often and you probably don't want to miss out on added stability and features. You could run updated manually, but why not schedule the updates in the background to make sure you are always running the latest stable versions, without ever having to worry about it.

If you've got a website that's heavy on your web server, you might want to run some processes like generating thumbnails or enriching data in the background. This way it can not interfere with the user interface. Linux has a great program for this called cron. It allows tasks to be automatically run in the background at regular intervals. You could also use it to automatically create backups, synchronize files, schedule updates, and much more. Welcome to the wonderful world of crontab.

Everyone knows that RAM is so much faster than a hard disk. To illustrate, while a current SATA disk has peak transfer rates of 375 MB/s, current RAM can do a mind blowing 12,500 MB/s! Normally only the system itself makes use of this ultra fast storage, but we can also access this space directly. And that opens a great window of opportunity.

I recently had to install a couple of squid servers to act as reverse proxies for a webcluster. You can teach the squid server to stand in between in the end users and the webservers, and to store all the static content ( .jpg .flv .css .htm for example ) in the RAM. This saves a lot of I/O and bandwidth on the webservers, and it can really speeds up a site. And the end of the road the webservers' load dropped with 92%. But before all this worked, I had to run through a massive config file and since the squid config file is their manual at the same time, it's about 5000 lines long. So I had to find out a way to filter only the important settings from the config file.

Ever wanted to change the crontab of a server, but got an editor on screen that you're totally unfamiliar with? There are a lot of causes for this annoyance, but one is that somebody recently installed or used midnight commander (mc) which for whatever reason seams to overrule your session's default editor.