Category: Linux

Linux is my primary operating system. I used it on the servers, desktops, laptops, netbooks, and even mobile phones since approximately 1997. I’ve tried a number of distributions over the years, and even created a couple myself. I still look around sometimes to see what others are up to. But most of my machines are running some sort of Red Hat – either a quick and easy Fedora Linux, or a stable and secure Red Hat Enterprise Server, or a cheaper CentOS alternative.

And while by now I am very comfortable in the Linux environment (both graphical and command line), I still discover a lot of new and interesting things about it. When I come across something worthy, I usually share it with the rest of the Open Software world, using this category.

OpenSSH 5.4 released

Now that I have a bit more time on my hands, I am catching up with all the RSS feeds, news, and announcements that I’ve missed recently. One of them was the release of OpenSSH 5.4 – a tool for pretty much every Linux user. There are a few interesting bits in the changelog:

Added a ‘netcat mode’ to ssh(1): “ssh -W host:port …” This connects stdio on the client to a single port forward on the server. This allows, for example, using ssh as a ProxyCommand to route connections via intermediate servers.

and

Add a ‘read-only’ mode to sftp-server(8) that disables open in write mode and all other fs-modifying protocol methods.

Also, it was mentioned that sftp got a whole lot of improvements, including tab completion, user-friendly sizes option, recursive transfers, etc.

Overall, a very welcome release.

Fighting Adobe AIR on Fedora 12

Until now I was completely and totally ignoring Adobe AIR. As far as I was concerned, it existed in a separate universe. But recently, quite a few Adobe AIR applications started to come up on my radar that I wanted to try. Yesterday, for example, I saw the Flickrroom, which sounds exactly like something that I need. So, I searched yum repositories, and then Google, and then I found this blog post, which provides clear instructions on how to install Adobe AIR on Fedora Linux. Followed everything to a step, and failed. Then Googled for more, tried, and failed. And no matter what I do, it seems to fail miserably.

As far as I can judge, Adobe AIR is installed on my system. I see two items in the main menu and they even work when I run them. But when I try to install any Adobe AIR application, I get a well known error message.

$ Adobe\ AIR\ Application\ Installer /home/leonid/Desktop/Flickroom.air
Application crashed with an unhandled SIGSEGVCrashlog has been dumped in /tmp/airCrashLogs/0219_1359_vG6AfW

This seems to indicate that I missing some dependency on my system, but I can’t which one. I’ve installed and updated everything that I could find a reference to. I’ve also looked through the crash dump for any hints, but nothing jumped at me.

Any ideas?

Fedora Linux history tour

Last weekend I went through a somewhat lengthy process of upgrading one of my servers from Fedora 6 to Fedora 12. The server is vital for a company that uses it, there is more than 2 TBytes of data on that machine, and I only had a weekend to go through the upgrade.

Fedora is a very dynamic distribution, with new releases coming out roughly every 6 month. An upgrade backward compatibility is maintained only for the last 2 releases. So, I had to first upgrade from Fedora 6 to Fedora 8, then from Fedora 8 to Fedora 10, and then finally from Fedora 10 to Fedora 12.

Of course such a long path would pretty much guarantee that things would break. But gladly I didn’t have to fix them for every upgrade, only once, after Fedora 12 upgrade was complete. So the actual upgrade routine was rather simple: insert DVD with the new version, reboot, upgrade, remove DVD, reboot. I was attempting to boot the system at least once into each new version to see how much stuff would break and if I notice anything going horribly wrong. Everything was going smooth, except for once machine refused to boot into the new version (Fedora 8, if I remember correctly). That didn’t stop me though. Just upgrade to the next one, and then to the next one, etc.

After the upgrade was finished, I installed the updates for Fedora 12 and started fixing things. The thing that I was worried for the most was Request Tracker (aka RT3) installation, which is a Perl application. As any proper Perl application, RT3 utilizes a whole lot of Perl modules from CPAN and every time Perl version is changed signifficantly, these modules should be downloaded and installed. Before, it was a rather slow, boring, and time consuming task. Now however things are much simpler. Before any perl upgrade just create an autobundle using the command “perl -MCPAN -e autobundle“. This will create a bundle with all your current Perl modules. After the upgrade is done, run “perl -MCPAN -e ‘install Bundle::Snapshot_2010_01_27_00‘” (where 2010_01_27_00 is the bundle version, as given to you by autobundle). Now Perl will download all modules and their requirements from CPAN and install them automatically. Pure magic.

Apart from RT3 only one thing broke. One that I would expect to break because I don’t follow the development of it that close. It was Samba. After the upgrade to Fedora 12 none of the users could connect to any of the file shares. “Access denied” was given no matter which username and password was used and what was the access level to the share. A quick Google search revealed the fix. Apparently, somewhere in between Fedora 6 and Fedora 12, Samba changed default back-end for storing credentials. A fix was as simple as adding a single line (“passdb backend = smbpasswd) to the configuration file, that switched Samba back to the old backend.

And that’s it! That’s all that broke and had to be fixed after an upgrade between 6 versions of a rather dynamic Linux distribution. Once again, I am really amazed by how well things are managed in Fedora. Kudos and congrats!

Miro – king of online video tools

My online video experience until very recently was limited to watching clips directly on YouTube and Google Video, and downloading episodes of Diggnation once in a while. There are of course more places and worthy video podcasts on the Web, but I just didn’t have the right tool, and I didn’t bother enough. But all of that had changed. A few days ago I stumbled upon Miro.

So, what’s Miro? Miro is a cross-platform (works on Linux, Mac, and Windows) application for downloading and watching online videos. It has a really simple and straightforward interface and does a lot of magic by itself. You just search for things that you are interested in – either by keyword or by category – review the list of results, subscribe to shows that you like and Miro automatically downloads them to your computer. You can watch those shows any time later. Even when you are not connected to the Internet (such as on the airplane for example).

You can search through downloads, sort them in a number of ways, etc. After you have seen the video, you can either delete it or keep it. If you do nothing about it, Miro will keep it on your computer for a few days (defaults to 5), and then will delete it to save some space.

Miro also comes with a built-in video player, so you don’t need any external ones installed. On Linux, Miro supports two back-ends – gstreamer and xine. I had a problem with gstreamer not playing any audio, so I switched to xine and everything is working nicely now. As an extra bonus, Miro’s video player remembers your last position for every video you played. So if you just stop the playback and decide to continue later, you won’t have to fast forward – Miro will just automatically start playing from the point where you stopped.

Miro supports a number of sites for video downloads. With YouTube, for example, it downloads a high definition (HD) version of the video by default, if its available. Also, torrent sites are supported and Miro handles them automatically as well.

Miro is such a simple and useful tool that it changes the way you see online videos. For example, before Miro I could only handle just a few podcasts, but now I am subscribed to dozens. It’s like an RSS aggregator for online video. It’ll make you want watch more videos. And it will make it extremely easy to do.

Obviously, I can go on and on about how wonderful it is, but instead of listening to me, you should get Miro and give it a try. Let me know in the comments if you liked it at all.

Interview with Jim Zemlin of Linux Foundation

cnet runs an inspiring interview with Jim Zemlin, the executive director of Linux Foundation. Interview covers the current state of Linux,

Linux has contributed over $10 billion in R&D value to the world. It runs every major financial trading platform in the world. It the only way the mobile industry could respond to the iPhone. It has over a $50 billion economy just in enterprise computing alone. It runs 90 percent of the world’s fastest supercomputers. It powers Sony cameras, Samsung televisions, your DVR, your GPS system and most of the major Web sites in the world. How on earth does this spell “trouble” for open source?

as well as expectations for the year 2010.

Linux is accelerating a major industry transition that is already well underway–an industry in which we pay for software and hardware to one in which we pay for neither.