Ubuntu

Running 32 bit executables on a 64 bit machine (Ubuntu Linux)

1 July, 2010 - 11:55
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I recently had this strange problem with running a 32 bit executable on a 64 bit machine. It executed just fine on 32 bit machines and some other 64 bit machine. But on this particular machine I got the strange error message:

bash: some32bitexecutable: No such file or directory

which is confusing because bash seems to complain that it does not find the executable, while I knew it was there. Using absolute paths and double checking the permissions didn't help.

The problem was however that the 32 bit runtime libraries were not available.

The fix on Ubuntu is to install the ia32-libs package, described as:

ia32 shared libraries for use on amd64 and ia64 systems.
This package contains runtime libraries for the ia32/i386 architecture, configured for use on an amd64 or ia64 Debian system running a 64-bit kernel.

(FYI: it will pull down some other packages too, like lib32gcc1, libc6-i386 and lib32stdc++6.)

C++-MEX files compilation problems under Ubuntu 8.04 (Hardy)

23 September, 2009 - 18:09

How unpleasant I may find it, sometimes I have to use some tools in Matlab at work. Today I stumbled on a problem with compiling MEX-files written in C++ on my Ubuntu 8.04 (Hardy Heron) box. To illustrate, I'll use the example C++ MEX file mexcpp.cpp provided with Matlab (Matlab r2007a) in the extern/examples/mex/ folder.

Out-of-the-box compilation with

mex mexcpp.cpp

gave the following warning:
Warning: You are using gcc version "4.2.4". The earliest gcc version supported with mex is "4.0.0". The latest version tested for use with mex is "4.2.0". To download a different version of gcc, visit http://gcc.gnu.org

Despite the warning a MEX-file mexcpp.mexglx was generated. However, its usage resulted in the following:
Invalid MEX-file '/foo/bar/mexcpp.mexglx': /matlabdir/sys/os/glnx86/libstdc++.so.6: version `GLIBCXX_3.4.9' not found (required by /foo/bar/mexcpp.mexglx).
As a sidenote: compiling MEX-files written in C also caused the warning message, but using the compiled MEX-files did not fail.

How to find out which version of Ubuntu you are running?

11 September, 2009 - 09:51
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How to find out which version of Ubuntu you are running?

Use one of the commands below:

lsb_release -a
cat /etc/lsb-release
cat /etc/issue

kthxbye

Eclipse TPTP woes in Ubuntu and how to solve it as non-root

19 August, 2009 - 14:09

Today, I wanted to do some profiling of a Java application in Eclipse (3.4 aka Ganymede) on my Ubuntu 8.10 box at work. Google pointed me to the Eclipse TPTP (Test & Performance Tools) platform, which I installed through the Eclipse plug-in installer thingy, that weird acting constantly blocking/reloading user interface located under the "help" menu (of all places!), but lets not get us carried away by that for the moment.

After installation (and the obligatory eclipse restart), I tried to use the new tool, but soon my enthusiasm was curbed as I got a nice red error message IWAT0435E An error occurred when connecting to the host on the monitor tab of the profile configuration dialog. No profiling for me, sir. Bummer.

Getting ready for what started to smell like another jumping through hoops session, I googled the warning and got to this eclipse bug report. Apparently, some component of TPTP requires a prehistoric version of libstdc++. Unfortunately, that version was not available anymore in the standard Ubuntu repositories since Ubuntu 8.04 or something.

Accented characters with qwerty keyboard (Ubuntu Linux)

23 March, 2009 - 10:25
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I prefer a qwerty keyboard for programming, but to write in my native language (Dutch) I need sometimes accented characters like ë, ï, é, etc, which do not have dedicated keys on a qwerty layout.

A handy way under Linux is to use a "compose key" ([Alt Gr] on my setup), which allows you to compose accented characters by entering the accent (umlaut, accent grave, ...) and the unaccented character separately.

Completion for Gnuplot under Ubuntu(/Debian) with rlwrap

20 April, 2007 - 14:46

The default install of gnuplot in Ubuntu/Debian does offer a crippled form of word completion, when compared to other distribution (Mandrake, Suse). For example, filenames can not be completed with pressing tab, which can be really annoying if you're used to have this sort of completion. The reason for this is some licensing issue with the readline library. A workaround is to compile Gnuplot with the right tweaks, but this is to much hassle for what it's worth for me.

Another solution, which can also be applied to other applications, is rlwrap. It's just a simple sudo apt-get install rlwrap away (with uni/multiverse repositories enabled).

Now I have filename completion in gnuplot with:

rlwrap -a -c gnuplot

And if you're not so keen on remembering this, just add the following alias to your .bashrc:

alias gnuplot='rlwrap -a -c gnuplot'

Nice.

Feh, yet another image viewer for Linux

1 August, 2006 - 10:12
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Some years ago, when I solely worked in Windows, I happily used Irfanview as image viewer. Under Linux I didn't found a real replacement for it, yet. I already tried Gwenview, Kuickshow, Kview, ImageMagick's display, xv and maybe some others, but all have their little quirks and annoyances concerning speed or usability.

Here's a new candidate for my image viewer list: Feh (available for Ubuntu in the universe repository). Linux.com has a short overview of feh. It's a command line application, so it has it shortcomings on the usability front, but it quite fast and has nice features (hot keys, different view modes, mouse control, directory traversal, ...).

Thunderbird: install spell check dictionary (under Ubuntu)

28 June, 2006 - 18:46

I had some difficulties in Ubuntu with installing a new spell check dictionary for my mail client Thunderbird. My native language is Dutch (Nederlands) and writing Dutch with a English spell checker active is not very interesting. I tried the methods explained at http://www.mozilla.com/thunderbird/dictionaries.html , but that didn't work. I got some message that the dictionary "has been succesfully installed", but that message did not reflect the truth.

I messed a bit with the installation script inside the spell-nl.xpi file, and found out that the dictionary would/should be installed to /usr/lib/mozilla-thunderbird/components/myspell, a directory that is only writable by the root user. Apparently the installation procedure did not detect the write failure. I could put the Dutch dictionary there as root user, but I looked a bit further and found out that installing the appropriate MySpell package (myspell-nl for me) is a much cleaner/safer solution. MySpell is the spell checker of OpenOffice.org, which is also used in Thunderbird.

My Ubuntu Breezy to Dapper upgrade experiences

25 June, 2006 - 16:00
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On friday 23 june 2006 I decided to upgrade my kubuntu powered laptop (Acer Travelmate 4002WLMi) from Breezy (aka 5.10) to Dapper Drake (aka 6.06). Here is a list (under construction) of my experiences with the upgrade so far. The merits/blames are not all addressed to (k)ubuntu, some are related to the fact that the software is upgraded too (KDE 3.5.3 instead of 3.4 for example). Moreover, some things might be related to stupid faults/wrong expectations of my own.

All in all, I'm not so satisfied with this Ubuntu upgrade as I expected to be, after all those "Ubuntu Dapper is the best" vibes in the linux community.