Adventures & experiences in contemporary technology
Recently, I had someone ask me how to create PNG files in SAS using ODS Graphics so I sought out the answer for them. Normally, the suggestion would have been to create RTF or PDF files instead but there was a specific need so a different approach was taken. Adding the something like following lines before an SGPLOT, SGPANEL or SGRENDER procedure does the needful:
ods listing gpath='E:\';
ods graphics / imagename="test" imagefmt=png;
Here, the ODS LISTING statement declares the destination for the desired graphics file while the ODS GRAPHICS statement defines the file name and type. In the above example, the file test.png would be created in the root of the E drive of a Windows machine. However, this also works with Linux or UNIX directory paths.
The Flatpak concept offers a useful way of getting the latest version of software like LibreOffice or GIMP on Linux machines because repositories are managed conservatively when it comes to the versions of included software. Ubuntu has Snaps, which are similar in concept. Both options bundle dependencies with the packaged software so that its operation can use later versions of system libraries that what may be available with a particular distribution.
However, even Flatpak depends on what is available through the repositories for a distribution as I found when a software update needed a version of the tool. The solution was to add PPA using the following command and agreeing to the prompts that arise (answering Y, in other words):
sudo add-apt-repository ppa:alexlarsson/flatpak
With the new PPA instated, the usual apt commands were used to update the Flatpak package and continue with the required updates. Since then, all has gone smoothly as expected.
Over the weekend, I finally got to fixing a problem that has affected Ubuntu 18.04 virtual machine for quite a while. The usual checks on Guest Additions installation and vboxsf group access assignment were performed but were not causing the issue. Also, no other VM (Windows (7 & 10) and Linux Mint Debian Edition) on the same Linux Mint 19.2 machine was experiencing the same issue. The latter observation made the problem intrinsic to the Ubuntu VM itself.
Because I install the Guest Additions software from the included virtual CD, I executed the following command to open the relevant file for editing:
sudo systemctl edit --full vboxadd-service
If I had installed installed virtualbox-guest-dkms and virtualbox-guest-utils from the Ubuntu repositories instead, then this would have been the command that I needed to execute instead of the above.
sudo systemctl edit --full virtualbox-guest-utils
Whichever configuration gets opened, the line that needs attention is the one beginning with Conflicts (line 6 in the file on my system). The required edit removes systemd-timesync.service from the list following the equals sign. It is worth checking that file paths include the correct version number for the Guest Additions software that is installed in case this was not the case. The only change that was needed on my Ubuntu VM was to the Conflicts line and rebooting it got the Shared Folder automatically mounted under the /media directory as expected.
My online travel photo gallery is a self-coded set of PHP scripts that read data from tables in a MySQL database. These tables are built from input XML files using a Perl script that itself creates and executes an SQL script. The Perl script also does some image processing using GraphicsMagick commands to resize images and to add copyright information and image framing. Because this processed one image at a time sequentially, it was taking several minutes to complete and only partly used the capacity of the PC that I used.
This led me to look at adding parallel processing and that is what brought me to looking at the Parallel::ForkManager Perl module. An alternative approach might have been to add new images in such a way as not to need the full run involving hundreds of image files, but that will take more work and I fancied having a look at parallelising things anyway.
If it was not there already, the first act would have been to install build-essential to get access to the cpan command. The following command accomplishes this:
sudo apt-get install build-essential
Once that is there, the cpan command needs to be run and some questions answered to get things going. The first question to answer is whether you want setup to be as automated as possible and the default answer of yes worked for me. The next question to answer regards the approach that cpan takes when installing modules and I chose sudo here (local::lib is the default value and manual is another option). After this, cpan drops into its own command shell. Here, I issued two more commands to continue the basic setup by updating CPAN.pm to the latest version and adding Bundle::CPAN to optimise the module further:
make install
install Bundle::CPAN
Continuing the last of these may need extra intervention to confirmation the suggested default of exit at one point in its operation and that takes a little time to complete. It is after this that Parallel::ForkManager can be installed using the following command:
install Parallel::ForkManager
That completed quickly and the cpan shell was exited using its exit command. Then, the new module was available in scripting after that. The actual use of this module is something that hope to describe in another post so I am ending this one here and the same process is just as applicable to setting up cpan and adding any other Perl CPAN module.
Much of the past weekend was spent getting a working Debian 10 installation up and running in a VirtualBox virtual machine. Because I chose the Cinnamon desktop environment, the process was not as smooth as I would have liked so a minimal installation was performed before I started to embellish as I liked. Along the way, I got to wondering if I could create virtual hard drives using the command line and I found that something like the following did what was needed:
VBoxManage createmedium disk --filename <full path including file name without extension> -size <size in MiB> --format VDI --variant Standard
Most of the options are self-explanatory part from the one named variant. This defines whether the VDI file expands to the maximum size specified using the size parameter or is reserved with the size defined in that parameter. Two VDI files were created in this way and I used these to replace their Debian 8 predecessors and even to save a bit of space too. If you want, you can find out more in the user documentation but this post hopefully gets you started anyway.
Recent curiosity about Java programming and Groovy scripting got me trying to start up the Eclipse IDE that I had install on my main machine. What I got instead of a successful application startup was a message that included the following:
!MESSAGE Exception launching the Eclipse Platform:
!STACK
java.lang.ClassNotFoundException: org.eclipse.core.runtime.adaptor.EclipseStarter
at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:466)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:566)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:499)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:626)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:584)
at org.eclipse.equinox.launcher.Main.run(Main.java:1438)
at org.eclipse.equinox.launcher.Main.main(Main.java:1414)
The cause was a mismatch between Eclipse and the installed version of Java that it needed in order to run. After all, the software itself is written in the Java language and the installed version from the usual software repositories was too old for Java 11. The solution turned out to be installing a newer version as a Snap (Ubuntu’s answer to Flatpak). The following command did the needful since Snapd already was running on my machine:
sudo snap install eclipse --classic
The only part of the command that warrants extra comment is the --classic switch since that is needed for a tool like Eclipse that needs to access a host file system. On executing, the software was downloaded from Snapcraft and then installed within its own bundle of dependencies. The latter adds a certain detachment from the underlying Linux installation and ensures that no messages appear because of incompatibilities like the one near the start of this post.
On checking the Site Health page of a WordPress blog, I saw errors that pointed to a problem with its SSL set up. The www subdomain was not included in the site’s certificate and was causing PHP errors as a result though they had no major effect on what visitors saw. Still, it was best to get rid of them so I needed to update the certificate as needed. Execution of a command like the following did the job:
sudo certbot --expand -d existing.com,www.example.com
Using a Let’s Encrypt certificate meant that I could use the certbot command since that already was installed on the server. The --expand and -d switches ensured that the listed domains were added to the certificate to sort out the observed problem. In the above, a dummy domain name is used but this was replaced by the real one to produce the desired effect and make things as they should have been.
It is amazing how the Windows folder manages to grow on your C drive and on in a Windows 7 installation was the cause of my needing to expand the VirtualBox virtual machine VDI disk on which it was installed. After trying various ways to cut down the size, an enlargement could not be avoided. In all of this, it was handy that I had a recent backup for restoration after any damage.
The same thing meant that I could resort to enlarging the VDI file with more peace of mind than otherwise might have been the case. This needed use of the command line once the VM was shut down. The form of the command that I used was the following:
VBoxManage modifyhd <filepath/filename>.vdi --resize 102400
It appears that this also would work on a Windows host but mine was Linux and it did what I needed. The next step was to attach it to an Ubuntu VM and use GParted to expand the main partition to fill the newly available space. That does not mean that it takes up 100 GiB on my system just yet because these things can be left to grow over time and there is a way to shrink them too if you ever need to do just that. As ever, having a backup made before any such operation may have its uses if anything goes awry.
Having made plenty of use of grep on the Linux/UNIX command and findstr on the legacy Windows command line, I wondered if PowerShell could be used to search the contents of files for a text string. Usefully, this turns out to be the case but I found that the native functionality does not use what I have used before. The form of the command is given below:
Select-String -Path <filename search expression> -Pattern "<search expression>" > <output file>
While you can have the output appear on screen, it always seems easier to send it to a file for subsequent and that is what I am doing above. The input to the -Path switch can be a filename or a wildcard expression while that to the -Pattern can be a text string enclosed in quotes or a regular expression. It works well once you know what to do so here is an example:
Select-String -Path *.sas -Pattern "proc report" > c:\temp\search.txt
The search.txt file then includes both the file information and the text that has been found for sake of checking that you have what you want. What you do next is up to you.
After a recent upgrade to Linux Mint Debian Edition 3 in a VirtualBox virtual machine that I had running its predecessor, I began to notice that background images were being loaded with more washed out of faded colours. This happened at startup so selecting another background image worked as intended until the same thing happened to that after a system restart.
This problem is not new and has affected the Cinnamon desktop in the main Linux Mint variant (the one that is based on Ubuntu) and issuing the following command in a terminal session is a suggested solution:
gsettings set org.cinnamon.muffin background-transition fade-in
In my case, that solved the problem and desktop background image display is as it should be since I executed the above. All it took was a change to a system setting.