Adventures & experiences in contemporary technology
With my tendency to apply Linux updates using the command, I was happy to see that something similar was possible in FreeBSD too. The first step is to fire up a terminal session and drop into root using the su command. That needs the root superuser password in order to continue and the next step is to update the local repositories using the following command:
pkg update
After that, it is time download updated packages and install these by issuing this command:
pkg upgrade
Most of the time, that is sufficient but I discovered that there are times when the above fails and additional interventions are needed. What I had uncovered were dependency error messages and I set to looking around the web for remedies to this. One forum question that was similar to what I had met with the suggestion of consulting the file called UPDATING in /usr/ports/. An answer like that looks unhelpful but for the inclusion of advice where extra actions were needed. Also, there is a useful article on updating FreeBSD ports that gives more in the way of background knowledge so you understand the more about what needs doing.
Following both that and the UPDATING file resulted in my taking the following sequence of steps. The first act was to download and initialise the Ports Collection, a set of build instructions.
portsnap fetch extract
The above is a one time only action so future updates are done as follows:
portsnap fetch update
With an up to date Ports Collection in place, it was time to install portman:
pkg install portman
A look through /usr/ports/UPDTAING revealed the commands I needed for updating Python and Perl to address the dependency problem that I was having:
portmaster -o devel/py-setuptools27 devel/py-setuptools
portmaster -r py\*setuptools
With those completed, I re-ran pkg update again and all was well. The extra actions needed to get that result will not get forgotten and I am sharing them on here so I know where they are. If anyone else has use for them, that would be even better.
With UNIX being the basis of Linux, I have a soft spot for trying out any UNIX that can be installed on a PC. For a while, I had OpenSolaris on the go and even vaguely recall having a look at one of the BSD’s. However, any recent attempt to install one of the latter, and there are quite a few around now, got stymied by some sort of kernel panic caused by using AMD CPU’s. With the return to the Intel fold arising from the upgrade of my main home PC last year, it perhaps was time to try again.
The recent release of FreeBSD 10.0 was the cue and I downloaded a DVD image for a test installation in a VirtualBox virtual machine with 4 GB of memory and a 32 GB virtual hard drive attached (expanding storage was chosen so not all the allocated space has been taken so far). The variant of FreeBSD chosen was the 64-bit x86 one and I set to installing it in there. Though not as pretty in appearance as those in various Linux distros, the installer was not that user unfriendly to me. Mind you, I have experience of installing Arch Linux so that might have acclimatised me somewhat.
Those installation screens ask about the keyboard mapping that you want and I successfully chose one of the UK options. There was limited opportunity for adding extras though there was a short list of few from which I made some selections. User account set up also was on offer and I would have been better off knowing what groups to assign for my personal user account so as to have to avoid needing to log in as root so often following system start up later. Otherwise, all the default options were sufficient.
When the installation process was complete, it was time to boot into the new system and all that was on offer was a command line log in session. After logging in as root, it was time to press pkg into service in order to get a desktop environment in place. The first step was to install X:
pkg install xorg
Then, it was time to install a desktop environment. While using XFCE or KDE were alternatives, I chose GNOME 2 due to familiarity and more extensive instructions on the corresponding FreeBSD handbook page. Issuing the following command added GNOME and all its helper applications:
pkg install gnome2
So that GNOME starts up at the next reboot, some extra steps are needed. The first of these is to add the following line into /etc/fstab:
proc /proc procfs rw 0 0
Then, two lines were needed in /etc/rc.conf:
gdm_enable=”YES”
gnome_enable=”YES”
The first enables the GNOME display manager and the second activates other GNOME programs that are needed for a desktop session to start. With each of these in place, I got a graphical login screen at the next boot time.
With FreeDSB being a VirtualBox Guest, it was time to consult the relevant FreeBSD manual page. Here, there are sections for a number of virtual machine tools so a search was needed to find the one for VirtualBox. VirtualBox support for FreeBSD is incomplete in that there is no installation media for BSD systems though Linux and Solaris are supported along with Windows. Therefore, it is over to the FreeBSD repositories for the required software:
pkg install virtualbox-ose-additions
Aside from the virtual machine session not capturing and releasing the mouse pointer automatically, that did everything that was needed even if it was the open source edition of the drivers and their proprietary equivalents. To resolve the mouse pointer issue, I needed to temporarily disable the GNOME desktop session in /etc/rc.conf to drop down to a console only session where xorg. conf could be generated using the following commands:
Xorg -configure
cp xorg.conf.new /etc/xorg.conf
In the new xorg.conf file, the mouse section needs to be as follows:
Section “InputDevice”
Identifier “Mouse0”
Driver “vboxmouse”
EndSection
If it doesn’t look like the above and it wasn’t the case for me then it needs changing. Also, any extra lines from the default set up also need removing or the mouse will not function as it should. The ALT+F1 (for accessing GNOME menus) and ALT+F2 (for running commands) keyboard shortcuts then become crucial when your mouse is not working as it should and could avert a panic too; knowing that adjusting a single configuration file will fix a problem when doing so is less accessible is not a good feeling as I discovered to my own cost. The graphics settings were fine by default but here’s what you should have in case it isn’t for you:
Section “Device”
### Available Driver options are:-
### Values: <i>: integer, <f>: float, <bool>: “True”/”False”,
### <string>: “String”, <freq>: “<f> Hz/kHz/MHz”
### [arg]: arg optional
Identifier “Card0”
Driver “vboxvideo”
VendorName “InnoTek Systemberatung GmbH”
BoardName “VirtualBox Graphics Adapter”
BusID “PCI:0:2:0”
EndSection
The next step is to ensure that your HAL settings are as they should. I needed to create a file in /usr/local/etc/hal/fdi/policy called 90-vboxguest.fdi that contains the following:
<?xml version=”1.0″ encoding=”utf-8″?>
<!--
# Sun VirtualBox
# Hal driver description for the vboxmouse driver
# $Id: chapter.xml,v 1.33 2012-03-17 04:53:52 eadler Exp $
Copyright (C) 2008-2009 Sun Microsystems, Inc.
This file is part of VirtualBox Open Source Edition (OSE, as
available from http://www.virtualbox.org. This file is free software;
you can redistribute it and/or modify it under the terms of the GNU
General Public License (GPL) as published by the Free Software
Foundation, in version 2 as it comes in the “COPYING” file of the
VirtualBox OSE distribution. VirtualBox OSE is distributed in the
hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
Clara, CA 95054 USA or visit http://www.sun.com if you need
additional information or have any questions.
-->
<deviceinfo version=”0.2″>
<device>
<match key=”info.subsystem” string=”pci”>
<match key=”info.product” string=”VirtualBox guest Service”>
<append key=”info.capabilities” type=”strlist”>input</append>
<append key=”info.capabilities” type=”strlist”>input.mouse</append>
<merge key=”input.x11_driver” type=”string”>vboxmouse</merge>
<merge key=”input.device” type=”string”>/dev/vboxguest</merge>
</match>
</match>
</device>
</deviceinfo>
With all that set, it is time to ensure that the custom user account is added to the wheel and operator groups using this command:
pw user mod [user name] -G wheel operator
Executing the above as root means that the custom account can run the su command so that logging in as root at the start of a desktop session no longer is needed. That is what being in the wheel group allows and the anyone in the operator group can shut down or restart the system. Both are facilities readily available in Linux so I fancied having them in FreeBSD too.
Being able to switch to root in a terminal session meant that I could go on to add software like Firefox, Libreoffice, GIMP, EMACS, Geany, Netbeans, Banshee and so on. There may be a line of opinion that FreeBSD is a server operating system but all of these make it more than passable for serving as a desktop one too. There may be no package management GUI as such and the ones that come with GNOME do not work either but anyone familiar with command line working will get around that.
FreeBSD may be conservative but that has its place too and being able to build up a system one item at a time teaches far more than getting everything already sorted in one hit. So far, there is enough documentation to get me going and I hope to see where else things go too. So far, the OS hasn’t been that intimidating and that’s good to see.
There is a bill making its way through the U.K. parliament at the moment that could reduce the power of copyright when it comes to images placed on the web. The current situation is that anyone who creates an image automatically holds the copyright for it. However, the new legislation will remove that if it becomes law as it stands. As it happens, the Royal Photographic Society is doing what it can to avoid any changes to what we have now. There may be the barrier of due diligence but how many of us take steps to mark our own intellectual property? For one, I have been less that attentive to this and now wonder if there is anything more that I should be doing. Others may copyleft their images but I don’t want to find myself unable to share my own photos because another party is claiming rights over them. There’s watermarking them but I also want to add something to the image metadata too.
That got me wondering about adding metadata to any images that I post online that assert my status as the copyright holder. It may not be perfect but any action is better than doing nothing at all. Given that I don’t post photos where EXIF metadata is stripped as part of the uploading process, it should be there to see for anyone who bothers to check and there may not be many who do.
Because I also wanted to batch process images, I looked for a command line tool to do the needful and found ExifTool. Being a Perl library, it is cross-platform so you can use it on Linux, Windows and even OS X. To install it on a Debian or Ubuntu based Linux distro, just use the following command:
sudo apt-get install libimage-exiftool-perl
The form of the command that I found useful for adding the actual copyright information is below:
exiftool -p “-copyright=(c) John …” -ext jpg -overwrite_original
The -p switch preserves the timestamp of the image file while the -overwrite_original one ensures that you don’t end up with unwanted backup files. The copyright message goes within the quotes along with the -copyright option. With a little shell scripting, you can traverse a directory structure and change the metadata for any image files contained in different sub-folders. If you wish to do more than this, there’s always the user documentation to be consulted.
At some point, I managed to lose the ability to have tab key based autocompletion on terminal sessions on my Ubuntu GNOME machine. Wanting it back had me turn to the web for an answer and I found it on a Linux Mint forum; the bash shell is so pervasive in the UNIX and Linux worlds that you can look anywhere for a fix like this.
The problem centred around the .bashrc file in my home area. It does have quite a few handy custom aliases and I must have done a foolish spring clean on the file sometime. That is the only way that I can explain how the following lines got removed:
if [ -f /etc/bash_completion ]; then
. /etc/bash_completion
fi
What they do is look to see if /etc/bash_completion can be found on your system and to use it for tab-based autocompletion. With the lines not in .bashrc, it couldn’t happen. Others may replace bash_completion with bash.bashrc to got a fuller complement of features but I’ll stick with what I have for now.
Linux and UNIX have the touch command for changing the creation dates and times for files. However, it also will create empty text files for you as well. In fact, there are times when I feel the need to do this sort of thing on Windows too and the following command accomplishes the deed when run in a Command Prompt window:
type nul > command.bat
Essentially, null output is sent to a file that is created anew, command.bat in this case. Then, you can edit it in Notepad (or whatever is your choice of text editor) and add in what you need. This will not work in Powershell so you need another command for that:
New-Item command.bat -type file
This uses the New-Item command, which also can be used to create folders as well if you so desire. Then, the command becomes the following:
New-Item c:\commands -type directory
Note that file on the previous example has become directory and there is the -force option should you need to overwrite what already exists for some reason…
That other use of the UNIX/Linux touch command can be performed from the Command Prompt too and here is an example command:
copy /b file.txt +,,
The /b switch switches on binary behaviour for the copy command though that appears to be the default action anyway. The + operator triggers concatenation and ,, gets around not having a defined destination because you cannot copy a file over itself. If that were possible, then there would no need for special syntax for changing the date and time for a file.
For doing the same thing with Powershell, try the following:
(GetChildItem test.txt).LastWriteTime=Get-Date
The GetChildItem command has aliases of gci, dir and ls and the last two of these give away its essential purpose. Here, it is used to pick out the test.txt file so that its timestamp can be replaced with the current date and time returned by the Get-Date command. The syntax looks a little more complex even if it achieves the same end. Somehow, that touch command is easier to explain. Are Linux and UNIX that complicated after all?
Unless you have access to SAS Enterprise Guide, being able to work on one project at a time can be a little inconvenient. It is possible to open up more than one Display Manager System (DMS, the traditional SAS programming interface) session at a time but you can get a pop up window for SAS documentation for second and subsequent sessions and you don’t get your settings shared across them either.
The cause of both of the above is the locking of the SASUSER directory files by the first SAS session. However, it is possible to set up a number of directories and set the -sasuser option to point at different ones for different sessions.
On Windows, the command in the SAS shortcut becomes:
C:\Program Files\SAS\SAS 9.1\sas.exe -sasuser "c:\sasuser\session 1\"
On UNIX or Linux, it would look similar to this:
sas -sasuser "~/sasuser/session1/"
The “session1” in the folder paths above can be replaced with whatever you need and you can have as many as you want too. It might not seem much of a need but synchronising the SASUSER folders every now and again can give you a more consistent set of settings across each and you don’t get intrusive pop up boxes or extra messages in the log either.
The last few weeks have seen me poking around with a few different operating systems to see how they perform. None of these were particularly in-depth in their nature but brushes with alternatives to what I currently use for much of the time. While I am too sure what exactly has kicked off all of this curiosity, all of the OS’s that I have examined have been of the UNIX/Linux variety. With the inclusion of Unity in the forthcoming Ubuntu “Natty Narwhal” 11.04, I am mindful of the need to be keeping an eye on alternative options should there ever be a need to jump ship. However, a recent brush with an alpha version has reassured me a little. Then there are interesting OS releases too and I recently forgot the Ubuntu password (a silly thing to do, I know) for my Toshiba laptop too so I suppose that a few things are coming together.
It was that latter development that got me looking in amazement at the impressive minimalism of CrunchBang Linux before settling on Lubuntu to see how it did; these were Live CD runs so I tried before I committed to installing. It helped that the latter was based on Ubuntu as its name suggests so I wasted little name in finding my way around the LXDE desktop. By default, everything supplied with the distro is lightweight with Chromium coming in place of Firefox. There’s no sign of OpenOffice.org either with offerings like Abiword coming in its stead. For the sake of familiarity, I started to add the weight of things without reducing the speed of things, it seems. Well, the speedy start-up wasn’t afflicted anyway. Being an Ubuntu clone meant that it didn’t long to add on Firefox using the apt-get command. LibreOffice was downloaded for installation using the dpkg command and it seems much more fleet-footed than its OpenOffice.org counterpart. As if these nefarious actions weren’t enough, I started to poke in the settings to up the number of virtual desktops too. All in all, it never stopped me going against what be termed the intent of the thing. In spite of what Linux User & Developer has had to say, I think the presentation of the LXDE desktop isn’t unpleasant either. In fact, I reckon that I quite like it and the next thing to do is to restore the entry for Windows 7 on the GRUB menu. Well, there’s always somthing that needs doing…
While I may have learned about it after the event, the release of Debian “Squeeze” 6.0 was of interest to me too. Well, I have used it a fair bit in the last few years and retain a soft spot for it. The new release comes on two kernels: GNU/Linux and FreeBSD. Regarding the latter, I did try having a look but it locked up my main home PC when I tried booting it up in a VirtualBox virtual machine. Given that it’s a technical preview anyway, I think it better to leave it mature for a while no matter how fascinating the prospect may be. Or is it VirtualBox 4.x that hasn’t around long enough? Debian’s latest Linux incarnations showed no such inclinations though I found that the CD ISO image that I’d downloaded didn’t give such a complete system when I fired it up after doing the installation. Being someone that knows his way around Linux anyway, it was no problem to add the missing pieces using apt-get though that’d stop it being an option for new users unless the DVD installation yields more complete results. Other than that, it worked well and I lost no time getting to grips with the OS and it’s gained a much fresher feel than version 5.x (“Lenny”). In summary, I look forward to continuing my investigations of the new Debian.
To round up my explorations of different UNIX/Linux operating systems, I have updated my test installations of Ubuntu 11.04. Initial looks at the next Ubuntu release weren’t so encouraging but things are coming along by all accounts. For one thing, Unity can be switched off in favour of the more familiar GNOME desktop that we’ve had for the last few years. The messages that popped up telling you that there’s no 3D graphics support on your machine have been replaced by graceful degradation to the GNOME and that’s no bad thing either. In case it hasn’t been so obvious, I am one of those who needs convincing by the likes of Unity and GNOME Shell so I’ll sit on the fence for a while. After all, there always are alternatives like LXDE if I want to decamp to something else entirely. One of the nice things about Linux is the amount of that we all have; it might be tricky to choose sometimes but it always is good to be able to find a niche somewhere else when someone makes a decision that doesn’t suit you.
It’s amazing what work can bring your way in terms of technology. For me, (GNU) Emacs Has proved to be such a thing recently. It may have been around since 1975, long before my adventures in computing ever started, in fact, but I am asking myself why I never really have used it much. There are vague recollections of my being aware of its existence in the early days of my using UNIX over a decade ago. Was it a shortcut card with loads of seemingly esoteric keyboard shortcuts and commands that put me off it back then? The truth may have been that I got bedazzled with the world of Microsoft Windows instead, and so began a distraction that lingered until very recently. As unlikely as it looks now, Word and Office would have been part of the allure of what some consider as the dark side these days. O how OpenOffice.org and their ilk have changed that state of affairs…
The unfortunate part of the Emacs story might be that its innovations were never taken up as conventions by mainstream computing. If its counterparts elsewhere used the same keyboard shortcuts, it would feel like learning such an unfamiliar tool. Still, it’s not as if there isn’t logic behind it because it will work both in a terminal session (where I may have met it for the first time) and a desktop application GUI. The latter is the easier to learn, and the menus list equivalent keyboard shortcuts for many of their entries, too. For a fuller experience though, I can recommend the online manual, and you can buy it in paper form too if you prefer.
One thing that I discovered recently is that external factors can sour the impressions of a piece of software. For instance, I was using a UNIX session where the keyboard mapping weren’t optimal. There’s nothing like unfamiliar behaviour for throwing you off track because you felt your usual habits were being obstructed. For instance, finding that a Backspace key is behaving like a Delete one is such an obstruction. It wasn’t the fault of Emacs, and I have found that using Ctrl+K (C-k in the documentation) to delete whole lines is invaluable.
Apart from keyboard mapping niggles, Emacs has to be respected as a powerful piece of software in its own right. It may not have the syntax highlighting capabilities of some, like gedit or NEdit for instance, but I have a hunch that a spot of Lisp programming would address that need. What you get instead is support for version control systems like RCS or CVS, along with integration with GDB for debugging programs written in a number of languages. Then, there are features like file management, email handling, newsgroup browsing, a calendar and calculator that make you wonder if they tried to turn a text editor into something like an operating system. With Google trying to use Chrome as the basis of one, it almost feels as is Emacs was ahead of its time, though that may have been more due to its needing to work within a UNIX shell in those far-off pre-GUI days. It really is saying something that it has stood the test of time when so much has fallen by the wayside. Like Vi, it looks as if the esteemable piece of software is showing no signs of going away just yet. Maybe it was well-designed in the beginning, and the thing certainly seems more than a text editor with its extras. Well, it has to offer a good reason for making its way into Linux too…
Recently, I had the opportunity to have a look at the Excel library engine again because I need to read Excel data into SAS. You need SAS Access for PC Files licensed for it to but it does simplify the process of getting data from spreadsheets into SAS. It all revolves around setting up a library pointing at the Excel file using the Excel engine. The result is that every worksheet in the file is treated like a SAS dataset even if there names contain characters that SAS considers invalid for dataset names. The way around that is to enclose the worksheet name in single quotes with the letter n straight after the closing quote, much in the same way as you’d read in text strings as SAS date values (’04MAR2010’d, for example). In order to make all of this more, I have added some example code below.
libname testxl excel 'c:\test.xls';
data test;
set testxl.'sheet1$'n;
run;
All of the above does apply to SAS on Windows (I have used it successfully in 9.1.3 and 9.2) but there seems to be a way of using the same type of thing on UNIX too. Again, SAS Access for PC Files is needed as well as a SAS PC Files server on an available Windows machine and it is the PCFILES engine that is specified. While I cannot say that I have had the chance to see it working in practice but seeing it described in SAS Online Documentation corrected my previous misimpressions about the UNIX variant of SAS and its ability to read in Excel or Access data. Well, you learn something new every day.
Using the command line to process images might sound senseless but the tools offered by ImageMagick certainly prove that it has its place. I have always been wary of using bulk processing for my digital photo files (some digitised from film prints with a scanner) but I do agree that some of it is needed to free up some time for other more necessary things. With this in mind, it is encouraging to see the results from ImageMagick and I can see it making a major difference to how I maintain my online photo gallery.
For instance, making thumbnail images for the gallery certainly seems to be one of those operations where command line bulk processing comes into its own and ImageMagick’s own convert command is heaven sent for this one. For resizing images, all that’s needed is the following:
convert -resize 40% input.jpg output.jpg
Add a spot of further shell scripting and even a dash of Perl and the possibilities for this sort of thing become clearer and this is but the pinnacle of the proverbial iceberg. The -rotate switch will do what the name suggests and there are a whole plethora of other options on tap. So long as you have Ghostscript on your system, conversion of graphics to Postscript (and Encapsulated Postscript too) and PDF files is possible with the -page option controlling the margin around the image itself in the resulting outputs. Unfortunately, portrait is the sole orientation on offer but a bit of judicious post processing will turn things around. Here’s a command that’ll do the trick:
convert -page 792×612+72+72 input.png ps2:output.ps
For retrieving image metadata like its resolution and size, the identify command comes into play. The -verbose option invokes the output of all manner of image metadata so using grep or egrep is perhaps advisable, especially for bulking processing with the likes of Perl. Having the ability to stream image metadata makes loading databases like MySQL less of a chore than the manual data entry that has been my way of doing things until now.