Linux goesZen

I often splice audio out from videos to have the audio track as a separate audio file, a mp3 or aac file depending on what’s in the original video so the audio is copied over unchanged, lossless. When doing so, the simple metadata syntax of ffmpeg (or avconv now) is very handy to properly tag [...]

Grabbing VHS video or capturing VHS tapes is essentially like digitising a TV video signal with means of a hardware grabber, some capture video card, or as in my case, with a USB video capture solution. And: it’s perfectly doable on Linux. In my case, I was using a stk1160 based USB stick, a cheap [...]

In case you can’t connect to your local SMTP server, for example from Perl’s Mail::Sendmail, make sure to check the following: It might be that localhost and the IP address Exim is listening on are not the same! Do this: $ netstat -anp | grep ” LISTEN ” This will output all the ports local [...]

A few days ago, after unplugging my Amazon Kindle from my computer, I switched it on and to my horror – the device was empty! All my clippings, all my books and PDFs transferred via USB onto the reader – gone! Just the default manual and the dictionaries where there. But then I thought: hey, [...]

Wget’s resume option is named “continue“. You can resume a broken, partial or incomplete download by adding the -c or –continue option to your set of switches. Just a note…

After debuggin the ssl_error_rx_record_too_long problem myself, it seems there is no one root of the error, not a single point to change. So here is how to track the error down on your system: Go to Apache’s /etc/apache2/ports.conf and comment out Listen on port 443, restart apache and see if you can connect to the [...]

On one of my systems I had to set my network to a strange configuration to get reliable connections: sudo ethtool -s eth0 autoneg on speed 10 duplex half I did this via ethtool after login, but then, I wanted this setting to be the default, after boot, automatically – I wanted to make the [...]

These photos illustrate how to do a RAM expansion on a Lenovo U160 – quite a few screws to undo.

Recently, it happened to me that Firefox started loading a completely white, blank page. Strangely, always the same pages remain empty while other pages load without problem. My first hunch was a misbehaving Add-On or Greasemonkey script. Deactivated everything – no effect. Then I began searching Google, mostly discovering Windows related threads with people tracking [...]

If you’re a bit old school or if you tend to work with multiple editors (multiple windows) of one application open (vs. having applications that offer tabs inside, like Firefox) you will get a problem when you want to cycle through these windows by pressing ALT+TAB. Unity by default groups windows of one application into [...]

This post is related to the popular question “How to change the hostname on Linux?“, as exim pulls the hostname from the “official sources” on debian. Edit /etc/hostname and set the short system name there. Edit /etc/hosts which contains the localhost entry and the system name entry, in the form <IP>   <Hostname_FQD version>   <Hostname> compare [...]

In this post we learn how to configure exim4 on Debian with Spamassassin and the sa-exim module. Installing and configuring We do the routines suggested here, only without clamav virus scanning. apt-get install sa-exim spamassassin spamc Then, as the installer tells us, we edit spamassassins config file to enable the spamassassin daemon called spamd by [...]

So, you’ve forked a repository on github or created a new one from scratch? And then, you decided to work on it on your local computer, and not with the online editor? Ok, Probably after you’ve changed something in the local cloned repo, you’d like to push it back to the online master repository at [...]

If you end up with no wlan after upgrading your Ideapad to Ubuntu to 12.04 Precise, then you are victim of a rare case: Ubuntu switched the wlan driver to an open source one for the b43 series of wireless card, like the Broadcom BMC4313 with PCI id 14e4:4727 that is used in the Ideapad [...]

After attaching a ReiserFS disk to a devel box, after sudo fsck /dev/sde2, I’ve got this error: fsck: Error 2 while executing fsck.reiserfs for /dev/sde2 This is not an issue with permissions or so, it’s simply the error that fsck can’t find the reiser related tools. Do this: sudo apt-get install reiserfsprogs and your’re all [...]

While the Dancer documentation recommends deploying Dancer apps + Apache with Apache being configured as a proxy, I wanted to run my Dancer app as I was used to from CGI::Application applications, as simple cgi script. This means I use the dispatch scripts located in /public, triggering them by the CGI interface of Apache with [...]

Most formats on YouTube already contain AAC audio. Thus it is possible to convert the videos you downloaded from YouTube (for example with the YouTube Video Download GreaseMonkey Plug-In) to audio-only files without transcoding (!) the audio once again (=preserving quality). $ ffmpeg -i “<input file>” -vn -acodec copy -metadata title=”<Title>” -metadata artist=”<Artist>” -metadata comment=”Ripped [...]

This here is a simple cheat sheet of CLI commands to move or migrate directories and sql databases from one machine to another: Dump a database table from MySQL: $ mysqldump -u <db-username> -<db-password> –opt –quote-names –allow-keywords –complete-insert <db-name> <db-table> > <output-file> Slurp a database table back into MySQL: $ mysql -u <db-username> –password=<db-password> -D [...]

If you see an error in your Apache2 logs “mod_fcgid: HTTP request length 131198 (so far) exceeds MaxRequestLen (131072)“ The defaults for fcgi have changed from Lenny (was 1GB) to Squeeze (is now 128KB) Solution is: Go to /etc/apache2/mods-available/fcgid.conf and add (here for 2GB): <IfModule mod_fcgid.c> … … # 2GB FcgidMaxRequestLen 2147483648 </IfModule> via Simple [...]

Ok, read: http://www.g-loaded.eu/2007/08/10/ssl-enabled-name-based-apache-virtual-hosts-with-mod_gnutls/ http://forceping.com/2010/03/18/mod_gnutls-sorgt-fur-namebased-ssl-virtualhosts/ http://www.outoforder.cc/projects/apache/mod_gnutls/docs/#example then install $ apt-get install libapache2-mod-gnutls then run $ a2enmod gnutls check if anything is configured in these files that would prevent apache2 from working with gnutls: nano /etc/apache2/httpd.conf nano /etc/apache2/apache.conf configure your virtual hosts, refer to the manual mentioned above on how to do that nano /etc/apache2/sites-enabled/000-default Possibly your [...]

tar cf – <path or file> | 7zr a -si <output>.tar.7z tar outputs to stdout (“-”, the minus), 7-zip, here 7zr, reads from stdin (“-si”) and outputs a 7zip file – all connected by the pipe.

If you, like me, get many “temporarily rejected RCPT <mail@example.com>: remote host address is the local host” messages in exim’s /var/log/exim4/mainlog log, then here’s what I found out to be the solution. So you’ve freshly installed exim or got a fresh install with Debian Squeeze? You did not tinker with the config files manually but [...]

If you want to trim, cut, chop or in any way edit a video on the command line, these commands here help you to get simple editing done with ffmpeg: Editing a section out from the middle of a video (with re-encoding): $ ffmpeg -i <input> -ss hh:mm:ss.000 -t hh:mm:ss.000 -sameq <output> (-ss seek to [...]

Here’s how to convert a video to a series / sequence of jpeg images, effectively converting every still frame into a jpg, with numbering, using the magic of ffmpeg: ffmpeg -i <input_video> -f image2 <output_name>%03d.jpg a more verbose variant: ffmpeg -i <input>.avi -r 1 -s WxH -f image2 <output>-%03d.jpeg To create a video from a [...]

Recently, on a very fresh install of Debian Squeeze I’ve noticed that on boot, the log said “Activating Swap… FAILED“. A look into /etc/fstab brought up nothing helpful: UUID=xyz none  swap    sw 0 0 seemed okay. So as it seems there was an error with the volume that was listed as swap. Then, listing partitions [...]

Go to the start page dctp.tv, and find the URI of the video you want to download. From the Flash caroussell, the links are a little hard to extract. Look at the source and look for URLs starting with “/filme/”. You’ll also find the cloud front URL there, or visit: http://dctptvv2.appspot.com/streaming_servers/   Then visit the [...]

Installing the newest generation of Wacom Bamboo, Bamboo P&T (Pen & Touch), Bamboo Pen, CTL-470, CTH-470, etc. tablets under Linux can be a pain. We hear that in kernel 3.3 they are supported out-of-the-box, but that’s in 2013! Until then, here’s how to do it under Ubuntu 10.10+, current Debian etc. Forget all other guides. [...]

Switch on debugging and depending on your swfupload version it tells you either “Invalid function name: StartUpload” or “Call to StartUpload failed“. Even more strange, it sometimes happens, sometimes doesn’t, depending on if the page was loaded or reloaded. The solution is: it’s caused by the swfupload element, the button, being inside a DOM element [...]

Simply put, scp can’t skip existing files on the target, nor can it compare them based on size or timestamp. Thus you can’t resume a former incomplete recursive copy of a directory without having to re-copy everything what’s already there. You have to use rsync for this more advanced logic. rsync -av –bwlimit=350 –progress –stats [...]

In case you want to simply see the traffic going in/out of your system, use ethstatus. Period.

I recently tried disabling a CPU in a multi CPU system to save power. The interesting find, it actually increases power draw on the system! Although this is far from being a scientific test, I saw on an idling system with two Xeon 5140 dual-core CPUs a 216-219W power draw. When I disabled core 1 [...]

fdisk does not support the newer very large disks, thus we need to rely on parted, which has the GPT option already built-in. In my case, I was installing large Hitachi HDS723030ALA640 3TB drives. > parted /dev/sdb (parted) mklabel gpt (parted) mkpart primary 0 -1 (parted) print (parted) quit The mkpart primary 0 -1 means [...]

Download balder10.img Wipe the stick with the proper drive /dev/sdb location with: dd if=/dev/zero of=/dev/sdd bs=512 count=1000 Go into qemu with this qemu -boot a -fda balder10.img -hda /dev/sdb a:> fdisk and create the primary drive exiting from qemu starte qemu again qemu -boot a -fda balder10.img -hda /dev/sdd format c: sys c: xcopy /E [...]

“mysqli extension is missing” error coming from phpMyAdmin means it can’t find the php-mysqli module, which is pretty standard. Install apt-get install php5-mysql then, php5-mysql replaced mysqli or integrates the fixes it originally supplied. After the apt-get install you will still get the error as you need to restart your server after that! Otherwise, in [...]

On ./configure, audacious-plugins may report that you will compile with AudioScrobbler client : no. In this case install libcurl4-nss-dev (curl with SSL support), run configure again and it will indicate yes.

Do apt-get install mysql-server to install the MySQL client, server-core, server-5.x and setup the daemon. A small wizard will come up to ask you basic things.MySQL has its own user-permission system, so it asks for the  database root user’s password first. If the wizard doesn’t come up, you can create the root user manually: $ [...]

On Debian Squeeze do this apt-get install fail2ban to install fail2ban on your system. Fail2Ban’s conf files live in /etc/fail2ban,  the structure of these config files is explained here. Fail2Ban comes with a number of prepared config files for various services.But these templates have to be “activated” by editing the /etc/fail2ban/jail.conf config file. It is [...]

Just doing apt-get install apache2 will give you a working Apache web server, but not one of the optimized variants. As a rule of thumb: apache2-mpm-prefork: every request gets its own (memory-separated) process apache2-mpm-worker: the multi-threaded Apache2, uses threads instead of processes and is generally faster than -prefork and might use less memory. As PHP [...]

Installation of the sshd on Debian is not by apt-get install sshd but by doing apt-get install ssh which will ask you (or assume) that you want to run the ssh-daemon. You can check after installation by doing ps aux | grep sshd if the daemon is actually up. No that you’ve got direct access [...]

The IBM x System server x3650-7979 51G came with two SAS 73GB drives. First I went into the Adaptec ServeRAID 8k menu by pressing CTRL-A on bootup. Ran the basic check drive function and then formed an array out of the two drives by ~preparing the drives indivdually for the array, then formed an array [...]

The xmms fork and winamp clone Audacious stores it playlists in: ~/.config/audacious with ~/.config/audacious/playlist.xspf being the default playlist. All user added playlists are then stored in ~/.config/audacious/playlists/playlist_<number>.xspf

In case you want to auction or sell your Laptop or an old hard disk, make sure people have a hard time retrieving your data. Download SystemRescueCD, for example. Boot into Linux (could be you have to change the boot order in BIOS) Use # fdisk -l to list installed drives on the machine. Use [...]

As shown in Combining two or more PFDs into one, merging pdf files is simple with gs (ghostscript): gs -dBATCH -dNOPAUSE -q -sDEVICE=pdfwrite -sOutputFile=finished.pdf inputfile1.pdf inputfile2.pdf I should be equally simple if you’ve got some JPG files among the files you want to merge, through gs input filters, but I couldn’t get it to work. [...]

No need to worry: this is the Apache’s internal dummy connection. Apache / Apache2 uses it to wake up dormant processes/ requests. Read this. There are a couple of ways to remove this noise from your logfiles. On my system I went down this path: Go to your http.conf file, or the file containing the [...]

Recently I’ve came across an error where I updated a RapidSSL certificate on a server. A first indication that things are a little different than a few years ago was that RapidSSL issued a 2048 instead 1024 bit RSA key. Still, I didn’t expect anything to behave differently  until I opened Mozilla Thunderbird. It complained [...]

At least on Ubuntu, you shouldn’t! sudo apt-get install tesseract-ocr (and more language specific packages available via apt!) This here are the basic steps to compile tesseract, the open-sourced OCR software that rivals commercial packages (on Ubuntu 11.04 and similar): sudo apt-get install subversion automake libtool leptonica-progs libleptonica libleptonica-dev svn checkout http://tesseract-ocr.googlecode.com/svn/trunk/ tesseract-ocr ./runautoconf Patch [...]

Der Fehler sieht so aus, dass wenn man in Sage Handwerk 2011 z.B.  auf Auswertung > Rechnungsausgangsbuch geht, der Datumsbereich außerhalb jeder vernünftigen Regionen ist: 1.1.1899 – 21.12.2999. Und wenn man versucht diesen zu ändern bekommt man eine Fehlermeldung über ein ungültiges Datum. Ähnliches gibt es zu bestaunen, wenn man ein Projekt öffnet und die [...]

Der Fehler tritt auf Client-Installationen auf. SCHRITT 1: Schaue nach, ob die lokale HWP Installation korrekt registriert ist! Wenn es sich um eine Demo-Version handelt, geht kurz nach dem Programmstart oben rechts ein Fenster auf und sagt, dass das Programm an “Sage Software” lizensiert sei! (Das passiert, wenn man bei der Installation eine der mitgelieferten [...]

Bei mir sah die Systemumgebung so aus: Ein im Netzwerk erreichbarer Server fährt eine “Einzelplatz/Server”-Installation von HWP2011.2 nebst MSSQL Server. Die Fehlermeldung erscheint auf einem Arbeitsplatzrechner, auf dem gerade von CD-ROM eine neue Client-Installation des “Handwerk” HWP 2011.2 der Sage Software GmbH installiert wurde. SCHRITT 1: Schaue nach, ob die lokale HWP Installation korrekt registriert [...]

Bei mir sah die Systemumgebung so aus: Ein im Netzwerk erreichbarer Server fährt eine “Einzelplatz/Server”-Installation von HWP2011.2 nebst MS SQL Server. Die Fehlermeldung erscheint auf dem “Server” selbst. SCHRITT 1: Schaue nach, ob die lokale HWP Installation korrekt registriert ist! Wenn es sich um eine Demo-Version handelt, geht kurz nach dem Programmstart oben rechts ein [...]

While you may use tools like dvddecrypter under Windows to rip (decrypt or mirror, without shrinking) a DVD 1:1 to disk, vobcopy is the weapon of choice under Linux. How to use vobcopy to decrypt the DVD to disk that means, you want to make an exact copy of the DVD file and folder structure [...]

Many modern filesystems provide the user with a facility to store arbitrary key/value-pairs along with files, so-called metadata. Wikipedia’s definition: Extended file attributes is a file system feature that enables users to associate computer files with metadata not interpreted by the filesystem, whereas regular attributes have a purpose strictly defined by the filesystem (such as [...]

When you want to get your nVidia graphics card working or similar tasks with restricted drivers, people on forums might refer you to the restricted-manager. In case you wonder why you can’t find it, can’t install it via apt-get etc, the answer is simple: it has been renamed to jockey. From the Applications Menu it [...]

This article is an unfinished sketch! As a kind of follow-up to the FFserver streaming Guide, this guide here chronicles my work on getting vlc to act as medium size streaming server. Continuus asf/wmv video streaming Using the 2009-11-05 1.1.0-git snapshot version of vlc, the startup of the server and thus quality of the stream [...]

This article is an unfinished sketch! Automating tasks in in Blender‘s NLE, the Sequence Editor, via the Python API can be a tricky task. Most I’ve achieved so far I managed by trial and error. For example, I’ve found the docs to be quite unclear on how to add Video Effects via the API, so [...]

Sometimes, for example when you’ve got games from the 90s on CD-ROM lying around, you might want to back them up to preserve the data before the CDROM becomes unreadable – especially when the only copy you’ve got left is a backup itself Many games in during the nineties where so-called Mixed-Mode CD-ROMs, which means [...]

Here is my log of what I did to get a decently running Ubuntu Linux install on a Lenovo U160 11″ subnotebook. Now with updates for Ubuntu 11.04 (scroll down)! 1. Display trouble – black screen on boot As of this writing, a specific bug-fix addressing issues with the U160′s display panel has not yet [...]

Clone To get a remote mercurial repo local, we use the clone command. If this repo does not expose a public URL, we can do this clone equally well via ssh: hg clone ssh://user@server:port//path/to/repo/ /path/to/local/repo hg clone [OPTION]… SOURCE [DEST] Notice the double slashes after the server’s port, it doesn’t work with a single slash. [...]

Most elegant, open-source and completely free solution: ghostscript. gs -dBATCH -dNOPAUSE -q -sDEVICE=pdfwrite -sOutputFile=finished.pdf inputfile1.pdf inputfile2.pdf ghostscript (gs) is pre-installed in most linux distributions. Note: Find our in Merging multiple pdf files and jpg files into one PDF how to merge JPGs and PDFs into one PDF.

This is a follow up post to Creating a software RAID 1 as basis for an LVM drive. The basic steps of adding a disk to a volume group are for example explained here. What makes our process described here unique is that it uses an underlying set of two disks bundled as RAID 1 [...]

Coming from Window, audiophile users probably miss EAC (exact audio copy) as a reliable application to rip CDs as accurate as possible. Others relied on dbpowerAmp and it’s network of CD track checksums to verify what has been read from a CD by the disk drive. On Ubuntu Linux, mostly Rhythmbox or banshee will take [...]

Varnish is a high speed caching daemon or HTTP accelerator. I recently learned some lessons while implementing it on a host. I’d like to share here some bits of information which might be useful to others struggling with their install. Config file locations If you’ve installed varnish via apt-get install varnish, on Debian 5.0 the [...]

In order to upgrade a running server via ssh from Debian Etch 4.0 to Lenny 5.0 I basically followed these steps here and had a perfect result. Change every line in /etc/apt/sources.list having “etch” to “lenny”, then: > aptitude update Once this is done we will want to upgrade first the core apt packages > [...]

In some cases it might be wise to spin down a hdd in order to save power, reduce noise or whatever. Most people will tend to let the system manage spin up/down of a hard drive, and mostly this feature is used on portable laptops to save battery energy. On an always-on desktop machine it [...]

SD cards and portable storage is getting increasigly large. So before you dump gigabytes of data onto these chips, it’s a good idea to check if the SD card, SDHC, CF-Card or USB Stick is actually in good shape by thoroughly testing the preformated media. On Windows, there are some nifty focused utils to do [...]

One of the first things you might do, probably after your PC broke down or the OS got unbootable, is to do a copy/ snapshot of the system hdd drive before you do a clean install of Windows XP, try to repeair the existing one or do something else. In my case the machine in [...]

When you do backups with rdiff-backup, browsing snapshots older than the current one might quite quickly become a cumbersome command-line orgy. There are a number of tools out there to ease the pain with a graphical frontend. The rdiff-backup Wiki neatly lists them here, but you will soon find out that they are cgi based, [...]

Not everyone is using *nix OS on their computers. Recently, I had a problem with another machine that was stuck in an endless loop of the login screen, completely preventing a proper startup of the machine. The story was that the machine got a few hardware problems after transport which lead to DRAM replacement and [...]

While wanting to use DVD::Rip, Thoggen DVD Ripper and GnomeBaker to copy (or backup) a DVD today, I encountered the strange “Error trying to open: device or resource busy” on my Ubuntu box today. I solved this by freeing the dvd drive from system access with: sudo umount /dev/sr0 and everything worked. BTW: For DVD [...]

Live http streaming (specs here) is essentially a number of short video segments (~10 seconds each) and a permanently updated index file (.m3u8) that tells the iPhone where to fetch the next segment. Each segment is x264 video in a mpeg ts container. You can setup a working streaming chain using ffmpeg as input, a [...]

Compiling a recent/up-to-date vlc from source, from the latest SVN can be a pain as vlc has LOTS of dependencies. It can be, but it must not. Below I’m goint to present a number of strategies to take the hurdles and get a (more of less) working version of a recent vlc. I’d like you [...]

When you use ffmpeg to, for example, extract audio and video as seperate streams, or if you import it into Blender’s fabulous NLE, the Sequence Editor, you might encounter a different length of the audio and video part of the video. Call this audio video offset, audio video mismatch or simply audio video runtime/length difference [...]

This post is meant as a FAQ, an introductory guide and a general reference manual for  streaming video with ffmpeg‘s FFserver. It’s is mainly the stuff I found out while setting up ffserver myself, and fills in some bits the official docs leave out. Be sure to use a very up-to-date version (and proper combination) [...]

This guide is mostly referring to Debian Etch (4.0). Go to the bottom for ffmpeg on Debian Squeeze (6.0) Before you start, it might be useful to again read the post How do I compile stuff. Okay, here is how you build a recent binary of ffmpeg from source. Please be aware that configure switches [...]

Having an eye on recent developments in the field of storage, data archival and file systems, I think one can say that one of the more interesting approaches towards saving data on disk is the idea to flatten folder hierarchies and in turn introduce a filesystem that is based on tags. Each file can be [...]

Recently, while using an USB memory stick formatted in FAT32, I accidentally deleted a few files. My first idea while sitting on a Windows machine was to seek for a simple utility from the DOS world to get the files back. I thought it would be a no-brainer, but after wading through tons of Google [...]

Recently, I installed a dual-boot OS on a brand-new laptop, absolutely fresh system, no OS, no formatted disc. I started with Microsoft XP and after the basic install was complete, I added vlc-0.9.9 to test DVD playback. Surprise: I did not work. Although vlc should be able to playback a DVD without any further decryption [...]

Basically, every dir that is under your world-browsable path in your www directories will be accessible. Under normal conditions, that’s exactly what you want. For example a domain example.com pointing to /var/www/example.com will allow users to browse around in all subdirectories of /var/www/example.com. Now, what if you add directories to this path you want to [...]

Today I had a strange error while trying to download my emails from my POP3 account. I am using Thunderbird and after downloading a few messages it stopped and spit out an error: “The RETR command did not succeed. Error retrieving a message. Mail server mail.example.com responded [SYS/PERM] could not read message file.” on a [...]

Following Alvaro’s guide today, to repair my broken printer support after my dist-upgrade from 6.04 to Ubuntu 8.04 (amd64!) with version 3.9.2 of hplip from sourceforge. I ran into some issues I’d like to share. After the process, the printer properly showed up in the System Setup > Printer Window and seemed to work okay, [...]

I recently had the idea of trying to use a NFS (Network File System) share over the network and did a bit of research about it. Here are my results: As became obvious, the idea is not that new, with threads dating back to the 80s (here and here). The most important concern seems to [...]

Using mercurial (hg) recently, I came across an interesting problem. I had a number of files, properly dated back to their modification time by the filesystem (file_v1.ext was from 2008-June, file_v2.ext was from 2008-Aug etc…). In order to get versioning on these files finally right, I thought about adding them to a mercurial repository, thus [...]

Using redundant drives, keeping backups etc. might help to keep your data save. Anyway, being a bit more ahead of the curve is better than just waiting for harddrive failure. Now, how can we improve the overall management of our drives and how can we estimate when it’s getting likely that a drive fails. What [...]

After 3 years of solid service, it was time to update a few machines running Ubuntu 6.06 LTS Dapper Drake. A complete system wide upgrade is called a DistUpgrade – in contrary to updating/upgrading individual packages installed on your system, usually done with apt-get update && apt-get upgrade. Be sure to read some more manuals [...]

The handy nano editor (official homepage, wikipedia) on linux/unix type systems is a very easy to use little text editor (far more intuitive than the much followed vi) and allows very efficient text editing once you get the knack of the keyboard shortcuts. Read the manual if you are completely new to it. Most functions [...]

Of course, emptying the trash is usually a right-click on the desktop-trash and that’s it. But sometime you’ve managed it to move something to the trash (i.e under sudo) where you’ve got insufficient rights to delete it once it is in trash. So here is the command to do this from the command line: Open [...]

Install mysql with apt-get install mysql. The mysql config file can be found at /etc/mysql/my.cnf. Note that additional conf files may be linked from this file. If you are running mysql on your server, this means a permanently running daemon (a persistent type of program) will be present. It serves database connections on standard port [...]

Torrent downloads (technically correct downloads via the BitTorrent protocol, filextension .torrent) are a resources saving way of providing large downloads for a large userbase. Made popular by the BitTorrent client torrent downloads can be handled by a number of clients – which is why so many do not speak of BitTorrent downloads that often anymore, [...]

Speaking for a debian based system, here is a short list of very essential and useful commands: To update your system: agt-get update, then apt-get upgrade. Also see: Installing/updating software on any Linux system. The whole domain of /etc/init.d/xxx scripts, most prominently /etc/init.d/apache2 force-reload.Also compare these posts: How do I exit the X Server from [...]

The RTMP (Real Time Messaging Protocol) protocol is a proprietary and closed source protocol developed by Adobe which is used to stream (mainly FLV) video off a media server, like the the Adobe Flash Media Server. Most probably you’ve come across this protocol while watching video on one of the video sites out there. About [...]

Using SSL as means to secure data connections to specific servers on the net is a widely adopted standard. One of the limitations of domains secured with SSL certificates is that a certificate needs to be hardcoded to be only valid for a single subdomain + top-level-domain combination, like www.example.com. If your sitestructure requires you [...]

Although this is definetly off-stopic for a linux blog, this strange symptom appeared while reviving an XP box with the SystemRescueCd Linux LiveCD recovery suite. The story was that the main drive C: with Windows XP Pro on it had a few defects and required a fresh XP install. Like certainly many systems these days, [...]

Installing wine, the windows emulator to execute dos/Win32 programm executables (.exe) under Xandros on the ASUS EeePC can be a bit challenging- but if you follow my guide you should have it up and running in a few minutes. Do this: 1. Open the console/a terminal by pressing CTRL + ALT + T 2. Paste [...]

Here is how to checkout a specific revision from a subversion (svn) controlled project (use the “-r” option): svn checkout -r <revision number> This can be handy in case you use subversion in a production environment, where having the latest version is less important than having a version you know and can rely on.

If you are trying to properly install a Netgear USB WLAN dongle model WG111v3 on an Ubuntu machine running the 64-bit variant – just give up! There are numerous tutorials telling you that it would work, in version v1, v2 or v3 of the hardware – but they are all referring to the 32-bit version! [...]

Watermarking a video with ffmpeg is simple – at least once you have the correct command line. Here is what I’ve figured out: ffmpeg -y -i ‘inputFile.mpg’ -vhook ‘/usr/lib/vhook/watermark.so -f /home/user/VideoTag.gif’ … I am using the older “-vhook” (video hook) functionality of ffmpeg here. Please be carful with the location of the watermark.so library. Depending [...]

When you use ffmpeg to transcode videos from various sources and in various sizes, formats and aspect ratios to a given destination format, you can’t rely on ffmpeg alone to produce the expected results. In this post we will have a look at how we can dynamically letterbox or pillarbox (black bars on the sides [...]

If you do letterboxing or cropping on your video with ffmpeg, you might get this error: “incorrect top pad size” In this case you managed to somehow screw up the values passed to ffmpeg for resizing/padding. Have a look at your command. If you are using a script to call ffmpeg, check the algorithm that [...]

At least on Ubuntu Feisty Fawn 7.04, doing this: apt-get install openssl-dev will give you an error: Reading package lists… Done Building dependency tree Reading state information… Done E: Couldn’t find package openssl-dev As a workaround, to use openssl and openssl-dev, use the openssl-dev components from another library: apt-get install libcurl3-openssl-dev Also note that libgsm-dev [...]

On linux, and most other unixes, you can chain commands by simply putting a “&&” in between. This shorthand version is often used on make/install procedures without explicitely explaining it. So when you next compile something on linux, use sudo ./configure && sudo make && sudo make install to execute everything in batch without further [...]

Every linux/unix based OS has a built-in scheduler, a tool to automate the execution of tasks/scripts/commands at a given time. This tool is the cron daemon. cron directories On debian 4.0 there are two procedures to add tasks to the cron table of events. The crontab and the cron directories: If you navigate the directory [...]

As the rise project recently found out, the pre-installed SAMBA daemon on the ASUS EeePC is an outdated version that has a security problem, allowing a knowledgeable user to gain root access on the system. The original arcticle is over here. The little machine is running version 3.0.24 of smbd, which is vulnerable to the [...]

Over time, even an ambitious project like the ASUS EeePC will run into first problems. Its growing userbase also means more focus from the black hat community. An important measure to keep a system healthy and secure is updating and other common linux security measures. Here is my growing/work-in-progress checklist for making the ASUS Eee [...]

When compiling a software package that is dependent on OpenSSL, it might happen that your compiler will give you the following error: configure: error: Cannot find OpenSSL’s <evp.h> or <hmac.h> in this case, the compiler wants to tell you that you haven’t the openSSL developer library installed. Do so by: sudo apt-get install openssl-dev on [...]

As simple as this: $ apt-get install mysql-common mysql-server mysql-server-5.0 a small wizard should as for a root password (for the mysql server), otherwise: $ mysqladmin -u root -p password ‘NewMysqlRootPassword’ You can create a database like this $ mysqladmin -p create TestDatabase and add users like this (allowing access to the just created db): [...]

Offering https:// (SSL secured encrypted connections) is a feature most demanding webmasters who care about their customer’s privacy will want to offer on any e-Commerce website. Here is a small how-to about configuring your apache to use SSL and how to install the required certificates. This is known as using a self-signed certificate. First, install [...]

While configuring, changing or testing stuff on a dedicated server, things might break or you lock yourself out. Things like that often happen while securing your server. Anyway, there is help! Most ISPs offer a rescue console or booting into a rescue system to undo unwanted changes or rescue data from a defunct system. The [...]

Running your own server is challenging. One of the first steps you should take though, are measures to make your system more secure and keep unwanted guests or intruders outside. In this simple how-to on securing a linux server, I’d like to mention a few basic steps I would recommend in order to harden your [...]

After wrangling with an older Kyocera printer on the Eee PC, the next level is to connect a newer HP LaserJet 1018. The Xandros printer management actually recognizes the device by the correct id, but as printing does not work right after connecting, this seems to be just the id that is transferred via the [...]

An up and running operating system exposes a number of services to the user or the network by running so called deamons in the background. These are the services you may be familiar with from the Microsoft Windows envirnment, where the Task Manager (opened with <CTRL>+<ALT>+<DEL>) lists all sorts of little programms humming away. No, [...]

Compiling an application or programm from source is actually not as complicated as it seems. In most cases and when everything is setup right, the procedure is as follows: Go to a directory where you have write permissions or become the superuser root Get the source of the application, for example from the web with [...]

When on console, you can exit the X Server, which is running in the background, with: /etc/init.d/gdm stop or later restart it with: sudo /etc/init.d/gdm restart The toggle shortcut to switch back to the X Server’s GUI is <CTRL> + <Alt> + <Backspace>

The are numerous scenarios possible, where a RAID system can get out of sync. That means that the data on one disk is not exactly the same as on the other drive – although these two disks should be in perfect sync all the time. But don’t panic, this is what RAID was actually made [...]

This is a short how-to to create and mount a software RAID 1 partitition. Before you start, it may be helpful to read this Then begin to mechanically install your new disks. Check the /dev directory. Your new disks should show up. In my case they were automatically labeled “sdb” and “sdc”, “s..” as these [...]

A really simple command to transcode a video file from one format/ container to another can be achived with ffmpeg -i inspectorgadget.ogg inspectorgadget.avi This illustrates the basic command-scheme ffmpeg uses. In this case ffmpeg transcodes an .ogg file to an .avi file (actually it just changes the container format). No further processing is done.

Managing installed software (so called packets) is pretty straightforward on linux systems like Debian. Go to the console and edit the /etc/apt/sources.list Sometimes the location is a bit different, like /etc/sources.list You can install software automatically from repositories, accessible via the internet. Adding a line like deb ftp://ftp.de.debian.org/debian/ unstable main to sources.list adds such a [...]

If you would like to ban a subnet, an IP address or a single country, most of these tasks can be done by using mod_rewrite and your .htaccess file. Start by writing Rewrite conditions that match against the REMOTE ADDR variable. Depending on the length of your regexp you can ban a complete network, a [...]

When connecting a Kyocera FS-1010 to an ASUS Eee PC the default configuration should recognize the printer on USB and properly set it up for printing. But, as I said, it should… Actually getting the Kyocera to work on the EeePC was a little bit harder. First I fiddled around with the configuration of the [...]

On ubuntu, for example, executing commands is normally under a user other than root. In fact, root is deactivated altogether to make the system more secure even for novice users. However, on certaincircumstances you need to do things as root. This is where su (switch user) comes into play, or sudo (switch user and do). [...]

On Linux, searching for files is easy with the find command. In order to search for a specific text pattern inside a file you can use this command: find . -name ‘*.php’ -exec grep ‘my text pattern’ {} ; the “-name” section limits the search to files matching the stated pattern, in this case only [...]

As I have no solution yet, this post must be considered work in progress (WIP). I am running Linux and plan on using an HomePNA (also called HPNA) phoneline network via an Allnet ALL0187 USB to HPNA adapter. My system recognized the device partly and is now using the “pegasus” driver – which as far [...]

When you figured out how to go to console on an ASUS Eee PC (btw it’s pressing CTRL+ALT+T), the next question will be “how do I become root on the system, or what’s the root password?”. At first, Xandros, the OS on the little machine, has root deactivated by default, so you can’t become root [...]

As you can see from reading this discussion, installing a cpan module, without root access, can be daunting. When you managed to install your own compiled Perl on a non-root account, this is in most cases earlier or later the next step/problem. Do this: login via ssh ssh remotehost.com -l myusername Mostly, follow this guide [...]

When using portable storage media like USB-Sticks, SD-Cards, Transflash cards or Memorysticks you do gamble a bit with your data. From multiple data losses on such devices I know that losing the piece itself is not the only way to surprisingly get rid of your files. Let’s discuss these two aspects: The threat of losing [...]

Although the EeePC’s desktop seems to be pretty locked up as the system is running Xandros Linux, you can enter the console by pressing [CTRL] + [ALT] + [T] and go on tweaking the OS.

A short how-to for awstats. Lately, when I found out analog falls short in terms of geo IP functionality, I decided to switch to awstats. Running debian and a webserver, I downloaded the awstats archive and extracted it on a reachable path within the www root of my server. Next I customized the shipped awstats [...]

One annoying thing on ubuntu and linux in general is the absence of the old and trusty true type fonts that are shipped with Mixrosoft Windows uses. But help is near: Microsoft has released these fonts for free and you can install them on any linux system with little effort. On ubuntu type sudo apt-get [...]

Ever wanted to get a decent ubuntu on an older PC, a legacy machine that you found down the cellar? Then you might run into weird trouble when installing from a live CD or DVD – the installer needs more than the available RAM While booting the system, press Ctrl+Alt+F1 to go to console Select [...]

There are multiple ways of moving folders from one machine to another. You could connect via FTP, download all stuff and then upload the folder to the other machine. But this approach would suffer from slow connections and a step in-between that is not really needed. So the best and easiest way ist to trasnfer [...]

Coming from Windows, doing simple tasks on linux or ubuntu can sometimes appear to be hard. To make things easier, here’s the routine to burn a video DVD on ubuntu: Use (!) tovid, a wrapper for all the underlying scripts and tools. If you haven’t installed it yet sudo apt-get tovid use tovid to create [...]

In the previous post you’ve learned how to share folders among pure linux machines. Now, in reality you’d like to access that securely hosted files on that linux server from a machine running Windows XP. Here’s how to achive that: On the server sudo apt-get install samba sudo gedit /etc/samba/smb.conf and add: workgroup = GROUP [...]

First post on the zen of linux. A good start would be a basic post about how to get multiple machines working on a shared folder. The way to go in the linux/unix world is to use the pretty stable and reliable NFS filesystem. At first, you have to select a machine you would like [...]