Adventures & experiences in contemporary technology
For as long as I have been programming with SAS, there has been the ability to test if a variable does or does not have one value from a list of values in data step IF clauses or WHERE clauses in both data step and most if not all procedures. It was only within the last decade that its Macro language got similar functionality with one caveat that I recently uncovered: you cannot have a NOT IN construct. To get that, you need to go about things in a different way.
In the example below, you see the NOT operator being placed before the IN operator component that is enclosed in parentheses. If this is not done, SAS produces the error messages that caused me to look at SAS Usage Note 31322. Once I followed that approach, I was able to do what I wanted without resorting to older more long-winded coding practices.
options minoperator;
%macro inop(x);
%if not (&x in (a b c)) %then %do;
%put Value is not included;
%end;
%else %do;
%put Value is included;
%end;
%mend inop;
%inop(a);
Running the above code should produce a similar result to another featured on here in another post but the logic is reversed. There are times when such an approach is needed. One is where a small number of possibilities is to be excluded from a larger number of possibilities. Programming often involves more inventive thinking and this may be one of those.
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.
One of the benefits of running Linux is the availability of virtual desktops and installing VirtuaWin was the only way to get the same functionality in Windows before the launch of Windows 10. For reasons known to Microsoft, they decided against the same sort of implementation as seen in Linux or UNIX. Instead, they put the virtual desktop functionality a click away and rather hides it from most users unless they know what clicking on the Task View button allows. The approach also made switching between desktops slower with a mouse. However, there are keyboard shortcuts that addresses this once multiple virtual desktops exist.
Using WIN+CTRL+LEFT or WIN+CTRL+RIGHT does this easily once you have mastered the action. Depending on your keyboard setup, WIN is the Windows, Super or Command key while CTRL is the Control key. Then, LEFT is the left arrow key and RIGHT is the right arrow key. For machines with smaller screens where multi-tasking causes clutter, virtual desktops are a godsend for organising how you work and having quick key combinations for switching between them adds to their utility.
On another website, I have had a contact form but it was missing some functionality. For instance, it stored the input in files on a web server instead of emailing them. That was fixed more easily than expected using the PHP mail function. Even so, it remains useful to survey corresponding documentation on the w3schools website.
The other changes affected the way the form looked to a visitor. There was a reset button and that was removed on finding that such things are out of favour these days. Thinking again, there hardly was any need for it any way.
Newer additions that came with HTML5 had their place too. Including user hints using the placeholder attribute should add some user friendliness although I have avoided experimenting with browser-powered input validation for now. Use of the required attribute has its uses for tell a visitor that they have forgotten something but I need to check how that is handled in CSS more thoroughly before I go with that since there are new :required, :optional, :valid and :invalid pseudoclasses that can be used to help.
It seems that there is much more to learn about setting up forms since I last checked. This is perhaps a hint that a few books need reading as part of catching with how things are done these days. There also is something new to learn.
There are times when you might need to drop back to a full screen terminal session from a graphical desktop environment when running Linux. One example that I have encountered is the installation of Nvidia’s own graphics drivers on either Ubuntu or Linux Mint. Another happened to me on Arch Linux when a Cinnamon desktop environment update left me without the ability to open up a terminal window. Then, the full screen command allowed me to add in an alternative terminal emulator and Tech Drive-in’s list came in handy for this. there might have been something to sort on a FreeBSD installation that needed the same treatment. This latter pair happened to me on sessions running within VirtualBox and that has its own needs when it comes to dropping into a full screen command line session and I will come to that later.
When running Linux on a physical PC, the keyboard shortcuts that you are CTRL + ALT + F1 for entering a full screen terminal session and CTRL + ALT + F7 for returning to the graphical desktop again. When you are running a Linux guest in VirtualBox and the host operating system also is Linux, then the aforementioned shortcuts do not work within the virtual machine but instead affect the host. To get the guest operating system to drop into a full screen terminal session, the keyboard shortcut you need is [Host Key] + F1 and the default host key is the right hand CTRL key on your keyboard unless you have assigned to something else as I have. The exit the full screen terminal session and return to the graphical desktop again, the keyboard shortcut is [Host Key] + F7.
All of this works with GNOME and Cinnamon desktop environments running in X sessions and I cannot vouch for anything else unless alternatives like Wayland come my way. Hopefully, this useful functionality applies to those other set-ups too because there are times when a terminal session is needed to recover from a mishap, rare though those thankfully are and they need to be very rare if not non-existent for most users.
On upgrading from Ubuntu GNOME 13.10 to Ubuntu GNOME 14.04, a few rough edges were to be noticed. One was the display of my chosen background image: it was garbled. Later, I discovered that there is a maximum width of 2560 px for background images in GNOME Shell these days and that things get messy beyond that.
In my case, the image width was around 6000 px and I was used to its getting resized in GNOME Shell 3.8 and its predecessors. It seems that the functionality got removed after that though so the workaround of manual image resizing in the GIMP needed to be employed. Though having big images open in memory creates an additional overhead, not handling them very well at all looks like a bug caused by setting 2560 px as a maximum screen width for the GNOME Shell panel and the complete removal of Nautilus from desktop rendering duties. Let’s hope that sense is seen with ever larger screen sizes and resolutions coming our way.
It’s the sort of thing that did get me looking at adding on Cinnamon 2.2 for a while before setting background image scaling using the indispensable GNOME Tweak Tool was discovered. LinuxG.net has a useful tutorial on this for anyone with such an adventurous streak in them. For now though, I am OK with my set up but the GNOME project’s focus on minimalism could affect us in other ways so I can see why Clem Lefebvre started the Cinnamon one primarily for Linux Mint and the desktop environment is appearing elsewhere too. After all, Gedit lost its menu bar in GNOME 3.12 so it’s just as well that we have alternative choices.
Update 2014-05-06: It seems that the desktop image bug that afflicts GNOME Shell 3.10 got sorted for GNOME Shell 3.12. At least, that is the impression that an Antergos instance in a VirtualBox virtual machine gives me.
GNOME 3.10 came out last month but it took until its inclusion into the Arch and Antergos repositories for me to see it in the flesh. Apart from the risk of instability, this is the sort of thing at which rolling distributions excel. They can give you a chance to see the latest software before it is included anywhere else. For the GNOME desktop environment, it might have meant awaiting the next release of Fedora in order to glimpse what is coming. This is not always a bad thing because Ubuntu GNOME seems to be sticking with using a release behind the latest version. With many GNOME Shell extension writers not updating their extensions until Fedora has caught up with the latest release of GNOME for a stable release, this is no bad thing and it means that a version of the desktop environment has been well bedded in by the time it reaches the world of Ubuntu too. Debian takes this even further by using a stable version from a few years ago and there is an argument in favour of that from a solidity perspective.
Being in the habit of kitting out GNOME Shell with extensions, I have a special interest in seeing which ones still work or could work with a little tweaking and those which have fallen from favour. In the top panel, the major change has been to replace the sound and user menus with a single aggregate menu. The user menu in particular has been in receipt of the attentions of extension writers and their efforts either need re-work or dropping after the latest development. The GNOME project seems to have picked up an annoying habit from WordPress in that the GNOME Shell API keeps changing and breaking extensions (plugins in the case of WordPress). There is one habit from the WordPress that needs copying though and that is with documentation, especially of that API for it is hardly anywhere to be found.
GNOME Shell theme developers don’t escape and a large border appeared around the panel when I used Elementary Luna 3.4 so I turned to XGnome Enhanced (found via GNOME-Look.org) instead. The former no longer is being maintained since the developer no longer uses GNOME Shell and has not got the same itch to scratch; maybe someone else could take it over because it worked well enough until 3.8? So far, the new theme works for me so that will be an option should there a move to GNOME 3.10 on one of my PC’s at some point in the future.
Returning to the subject of extensions, I had a go at seeing how the included Applications Menu extension works now since it wasn’t the most stable of items before. That has improved and it looks very usable too so I am not awaiting the updating of the Frippery equivalent. That the GNOME Shell backstage view has not moved on that much from how it was in 3.8 could be seen as a disappointed but the workaround will do just fine. Aside from the Frippery Applications Menu, there are other extensions that I use heavily that have yet to be updated for GNOME Shell 3.10. After a spot of success ahead of a possible upgrade to Ubuntu GNOME 13.10 and GNOME Shell 3.8 (though I remain with version 13.04 for now), I decided to see I could port a number of these to the latest version of the user interface. Below, you’ll find the results of my labours so feel free to make use of these updated items if you need them before they are update on the GNOME Shell Extensions website:
There have been more changes coming in GNOME 3.10 than GNOME Shell, which essentially is a JavaScript construction. The consolidation of application title bars in GNOME applications continues but a big exit button has appeared in the affected applications that wasn’t there before. Also there remains the possibility of applying the previously shared modifications to Nautilus (also known as Files) and a number of these usefully extend themselves to other applications such as Gedit too. Speaking of Gedit, this gains a very useful x of y numbering for the string searching functionality with x being the actual number of the occurrence of a certain piece of text in a file and y being its total number of occurrences.GNOME Tweak Tool has got an overhaul too and lost the setting that makes a folder path box appear in Nautilus instead of a location part, opening Dconf-Editor and going to org > gnome > nautilus > preferences and completing the tick box for always-use-location-entry will do the needful.
Essentially, the GNOME project is continuing along the path on which it set a few years ago. Though I would rather that GNOME Shell would be more mature, invasive changes are coming still and it leaves me wondering if or when this might stop. Maybe that was the consequence of mounting a controversial experiment when users were happy with what was there in GNOME 2. The arrival of Fedora 20 should bring with it an increase in the number of GNOME shell extensions that have been updated. So long as it remains stable Antergos is good have a look at the latest version of GNOME for now and Cinnamon fans may be pleased the Cinnamon 2.0 is another desktop option for the Arch-based distribution. An opportunity to say more about that may arrive yet once the Antergos installer stops failing at a troublesome package download; a separate VM is being set aside for a look at Cinnamon because it destabilised GNOME during a previous look.
The changes made to Nautilus, otherwise known as Files, in GNOME Shell 3.6 were contentious and the response of the Linux Mint was to create their own variant called Nemo from the previous version of the application. On the Cinnamon or MATE desktop environments, the then latest version of GNOME’s file manager would have looked like a fish out of water without its application menu in the top panel on the GNOME Shell desktop. It is possible to make a few modifications that help Nautilus to look more at home on those Linux Mint desktops and I have collected them here because they are useful for GNOME Shell users too. Here they are in turn.
Adding Application Menu entries to Location Options Menu
The Location Options menu is what you get on clicking the button with the cog icon on the right-hand side of the application’s location bar. Using Gsettings, it is possible to make that menu include the sort of entries that are in the application menu in the GNOME Shell panel at the top of the screen. These include an entry for closing the whole application as well as setting its preferences (or options). Running the following command does just that (if it does not work as it should, try changing the single and double quotes to those understood by a command shell):
gsettings set org.gnome.settings-daemon.plugins.xsettings overrides '@a{sv} {"Gtk/ShellShowsAppMenu": <int32 0>}'
Adding in the Remove App Menu GNOME Shell extension will clean up the GNOME Shell a little by removing the application menu altogether. If, for some reason, you wish to restore the default behaviour, then the following command does the required reset:
gsettings set org.gnome.settings-daemon.plugins.xsettings overrides '@a{sv} {}'
Stopping Hiding of the Application Title Bar When Maximised
By default, GNOME Shell can hide the application title bars of GNOME applications such as Nautilus on window maximisation and this is Nautilus now works by default. Changing the behaviour so that the title bar is kept on maximised windows can be as simple as adding in the ignore_request_hide_titlebar extension. The trouble with GNOME Shell extensions is that they can stop working when a new version of GNOME Shell is used, so there’s another option: editing metacity-theme-3.xml but /usr/share/themes/Adwaita/metacity-1. The file can be opened using superuser privileges using the following command:
gksudo gedit /usr/share/themes/Adwaita/metacity-1/metacity-theme-3.xml
With the file open, it is a matter of replacing instances of ' has_title="false" ' with ' has_title="true" ', saving it and reloading GNOME Shell. This may persevere across different versions of GNOME Shell should the extension not do so.
Disabling Recursive Search
This discovery is what led me to bundle these customisations in an entry on here in the first place. In Nemo and older versions of Nautilus, just typing with the application open would lead you down a list towards the file that you wanted. This behaviour was replaced by an automatic recursive search from GNOME Shell 3.6 where the search functionality was extended beyond the folder that was open in the file manager to its subdirectories. To change that to subsetting within the open folder or directory, you need to install a patch version of Nautilus using the following commands:
sudo add-apt-repository ppa:dr3mro/personal
sudo apt-get update && sudo apt-get upgrade
The first of these adds a new repository with the patched version of Nautilus while the second combination installs the patched version. With that done, it is time to issue the following command:
gsettings set org.gnome.nautilus.preferences enable-recursive-search false
That sets the value of the new enable-recursive-search option to false for searching within an open directory. It also can be found using Dconf-Editor in the following hierarchy: org -> gnome -> nautilus -> preferences. The obsession of the GNOME project team with minimalism is robbing users of some options and this would be a good one to have by default too. Maybe the others should be treated in the same way even if you need to use Gsettings or Dconf-Editor to change them to avoid clutter. Having GNOME Tweak Tool able to set them all would be even better.
There is a handy comand line utility called GNU Parallel that allows you to run Linux commands on more than one CPU core at a time to perform parallel processing of the task at hand. Here is a form of the command that is similar to one that I often use:
ls *.* | parallel gm convert -sharpen 1×3 {} sharpened_images/{}
What it does is pipe a list of files in a folder to GraphicsMagick for sharpening and outputting to a sharpened_images directory. The {} in the command is where the filenames go in the sharpening command.
This worked fine in Ubuntu GNOME 12.10 but stopped doing so after I upgraded to the next version. A look on the web set me to running the following command:
parallel --version
That produced output that included the following line:
WARNING: YOU ARE USING --tollef. IF THINGS ARE ACTING WEIRD USE --gnu.
Rerunning the original command with the --gnu option worked but there was a more permanent solution than using something like this:
ls *.* | parallel --gnu gm convert -sharpen 1×3 {} sharpened_images/{}
That was editing /etc/parallel/config with root privileges to delete the --tollef option from there. With that completed, all was as it should again and it makes me wonder why the change was made in the first place. Perhaps because of it, there even is a discussion about the possibility of removing the --tollef option altogether since it is raising more questions than it answers.
One thing that I like to do is peruse the installed applications on any computer system. In most cases, this is simple enough to do but there are some who appear to believe in doing away with that in favour of text box searching. It also seems that the GNOME have fallen into that trap with version 3.8 of GNOME Shell. You could add the Applications Menu extension that is formally part of the GNOME Shell Classic interface and I have done this too. However, that has been known to freeze the desktop session so I am not that big a big fan of it.
However, there is a setting that brings back those application categories in the overview screen and it can be set using dconf-editor. After opening up the application, navigate to org > gnome > shell using the tree in the left hand panel of the tool. Editing the app-folder-categories entry in the right hand panel is what adds the categories back for you. The default is [‘Utilities’, ‘Sundry’] and this needs to be changed to [‘Utilities’, ‘Games’, ‘Sundry’, ‘Office’, ‘Network’, ‘Internet’, ‘Graphics’, ‘Multimedia’, ‘System’, ‘Development’, ‘Accessories’, ‘System Settings’, ‘Other’].
Once the above has been completed, a change is noticeable in that you get a list of categories in the application overview screen and a split of application icons in the middle and categories down the right hand side. Clicking on a category brings up a new panel that contains the application within it and this can be closed again. Cycling through the categories is a process of opening and closing the different panels. The behaviour may be changed but the functionality remains and I have heard that this will be polished further in release 3.10 of GNOME Shell.
For those wanting to to exit all of this and get something like the old GNOME 2, it is possible to add the Classic Session. In Fedora 19, it’s a matter of issuing something like the following command:
sudo yum -y install gnome-classic-session
In reality, this is a case of adding a number of extensions and changing the panel colour from black to grey but it works without needing the category tweak that I described above. The Application Menu extension does need more stability hardening before I’d trust it completely though. There’s no point having a nicer interface if it’s going to freeze up on you too often.