Tag: linux

About

Linux (IPA pronunciation: /ˈlɪnʊks/) is a Unix-like computer operating system. Linux is one of the most prominent examples of free software and open source development; its underlying source code can be freely modified, used, and redistributed by anyone.

The Linux kernel was first released to the public on 17 September 1991, for the Intel x86 PC architecture. The kernel was augmented with system utilities and libraries from the GNU project to create a usable operating system, which later led to the alternate term GNU/Linux. Linux is now packaged for different uses in Linux distributions, which contain the sometimes modified kernel along with a variety of other software packages tailored to different requirements.

Predominantly known for its use in servers, Linux has gained the support of corporations such as IBM, Sun Microsystems, Dell, Hewlett-Packard, and Novell, and is used as an operating system for a wide variety of computer hardware, including desktop computers, supercomputers, and embedded devices such as mobile phones and routers.

From en.wikipedia.org/wiki/Linux

 

Tranfer all MySQL databases to another server

Recently I had to migrate all MySQL databases from one server to another. This was a one time only operation, so setting up replication wasn't an option. And restoring a backup on the new server involved more downtime than strictly necessary. I figured the most ideal way would be to dump the active MySQL directly into the new MySQL instance. And that's what I did.

Login automatically with SSH keys

With SSH you can securely login to any Linux server and execute commands remotely. You can even use SSH to transfer and synchronize files from one server to another. Automating these tasks can make your life easier, but normally SSH prevents that because it requires you to login every time. Well, not anymore, in this article I will show you how to connect to SSH without a password.

Synchronize files with rsync

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.

Delete files securely with shred

Deleting a file or reformatting a disk does not destroy your sensitive data. The data can easily be undeleted. That's a good thing if you accidentally throw something away, but what if your trying to destroy financial data, bank account passwords, or classified company information. What if you want to clean your computer before selling it for instance?

Survive heavy traffic with your webserver

Recently two of my articles reached the Digg frontpage at the same day. My web server isn't state of the art and it had to handle gigantic amounts of traffic. But still it served pages to visitors swiftly thanks to a lot of optimizations. This is how you can prevent heavy traffic from killing your server.

Make ISO images on Linux

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.

Schedule tasks on Linux using crontab

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.

Block brute force attacks with iptables

Since 2005 there has been an immense increase in brute force SSH attacks and though Linux is pretty secure by default, it does not stop evil programs from indefinitely trying to login with different passwords. Without proper protection your server is a sitting duck waiting for a bot to guess the right combination and hit the jackpot. But with just 2 commands we can stop that.

Dell expands linux offerings

According to Mark Shuttleworth, founder of the Linux distribution Ubuntu, Dell is pleased with the demand for Ubuntu computers. The company has been distributing computers with Ubuntu since May this year and is planning to expand the Linux offerings.

Create turbocharged storage using tmpfs

Everyone knows that RAM is so much faster than a hard disk. To illustrate, while a modern SATA disk has peak transfer rates of 375 MB/s, modern 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.

Cat a file, without the comments

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.

Change the default editor

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.