Technology Tales

Killing Windows processes from the command line

During my days at work, I often hear about the need to restart a server because something has gone awry with it. This makes me wonder if you can kill processes from the command line, like you do in Linux and UNIX. A recent need to reset Windows Update on a Windows 10 machine gave me enough reason to answer the question.

Because I already knew the names of the services, I had no need to look at the Services tab in the Task Manager like you otherwise would. Then, it was a matter of opening up a command line session with Administrator privileges and issuing a command like the following (replacing [service name] with the name of the service):

sc queryex [service name]

From the output of the above command, you can find the process identifier, or PID. With that information, you can execute a command like the following in the same command line session (replacing [PID] with the actual numeric value of the PID):

taskkill /f /pid [PID]

After the above, the process no longer exists and the service can be restarted. With any system, you need to find the service that is stuck to kill it, but that would be the subject of another posting. What I have not got to testing is whether these work in PowerShell, since I used them with the legacy command line instead. Along with processes belonging to software applications (think Word, Excel, Firefox, etc.), that may be something else to try should the occasion arise.

WARNING: No bars were drawn. This could have been caused by ORDER= on the AXIS statement. You might wish to use the MIDPOINTS= option on the VBAR statement instead.

What you see above is an error issued by a SAS program, akin to what a colleague at work recently found. The following code will reproduce this, so let us walk through the steps to explain a possible cause for this.

The first stage is to create a test dataset containing variables y and x, for the vertical and midpoint axes, respectively, and populating these using a CARDS statement in a data step:

data a;
    input y x;
    cards;
    1 5
    3 9
    ;
run;

Now, we define an axis with tick marks for particular values that will be used as the definition for the midpoint or horizontal axis of the chart:

axis1 order=(1 3);

Then, we try creating the chart using the GCHART procedure that comes with SAS/GRAPH and this is what results in the error message being issued in the program log:

proc gchart data=a;
    vbar x / freq=y maxis=axis1;
    run;
quit;

The cause is that the midpoint axis tick marks are not included in the data, so changing these to the actual values of the x variable removes the message and allows the creation of the required chart. Thus, the AXIS1 statement needs to become the following:

axis1 order=(5 9);

Another solution is to remove the MAXIS option from the VBAR statement and let GCHART to be data-driven. However, if requirements do not allow this, create a shell dataset with all expected values for the midpoint axis with y set 0 since that is used for presenting frequencies as per the FREQ option in the VBAR statement.

Resolving Windows Update Error 0x80244019 on Windows 10

In Windows 10, the preferred place to look if you fancy prompting an update of the system is in the Update & Security section of the Settings application. At the top is the Windows Update, and the process usually is as simple as pressing the Check for updates button. For most of the time, that has been my experience, but it stopped working on my main Windows 10 virtual machine, so I needed to resolve the problem.

Initially, going into the Advanced Options section and deselecting the tick box for Give me updates for other Microsoft products when I update Windows helped. However, it seemed a non-ideal solution, so I looked further. When it was then that I found that manually resetting a system's Windows Updates components helped others, I tried that and restarted the system.

The first part of the process was to right-click on the Start Menu button and select the Windows PowerShell (Admin) entry from the menu that appeared. This may be replaced by Command Prompt (Admin) on your system on your machine, but the next steps in the process are the same. In fact, you could include any commands you see below in a script file and execute that if you prefer. Here, I will run through each group in succession.

From either PowerShell or the Command Prompt, you need to stop the Windows Update, Cryptographic, BITS (or Background Intelligent Transfer Service) and MSI Installer services. To accomplish this, execute the following commands at a command prompt:

net stop wuauserv
net stop cryptSvc
net stop bits
net stop msiserver

With the services stopped, it is then possible to rename the SoftwareDistribution and Catroot2 folders so you can refresh everything to remove them. To accomplish this, execute the following pair of commands using either PowerShell or the Command Prompt:

ren C:\Windows\SoftwareDistribution SoftwareDistribution.old
ren C:\Windows\System32\catroot2 Catroot2.old

Once you have the folders renamed, then you can start the Windows Update, Cryptographic, BITS and MSI Installer services by executing the following commands in either PowerShell or the Command Prompt:

net start wuauserv
net start cryptSvc
net start bits
net start msiserver

Once these have completed, you may close the PowerShell or Command Prompt window that you were using and restart the machine. Going into the Update & Security section of the Settings tool afterwards and pressing the Check for updates button now builds new versions of the folders that you renamed, and this takes a little while longer than the usual update process. Otherwise, you could let your system rebuild things in its own time. As it happens, I opted for manual intervention and all has worked well since then.

Creating soft and hard symbolic links using the Windows command line

In the world of UNIX and Linux, symbolic links are shortcuts, but they do not work like normal Windows shortcuts because you do not jump from one location to another with the file manager's address bar changing what it shows. Instead, it is as if you see the contents of the directory at another quicker to access location in the file system, and the same sort of thinking applies to files too. In some ways, it is like giving files and directories alternative aliases. There are soft links that point to the name of a given directory or file, and hard links that point to actual files or directories.

For a long time, I was under the mistaken impression that such things did not exist on Windows until I came across the mklink command, which came with the launch of Windows Vista at the start of 2007. While this feature might not be widely known, it demonstrates that Windows did adopt some UNIX and Linux capability long before other UNIX-like features, such as virtual desktops, were introduced in Windows 10.

By default, the aforementioned command sets up symbolic links to files and the /D switch allows the same to be done for directories too. The /H switch makes a hard link instead of a soft link, so we get much of the functionality of the ln command in UNIX and Linux. Here is an example that creates a soft symbolic link for a directory:

mklink /D shortcut target_directory

Above, shortcut is the name of the symbolic link file and target_directory is the destination to which it links. In my experience, it works best for destinations beyond your home folder and, from what I have read, hard links may not be possible across different disks either.

Windows commands for setting default applications for opening certain file types

On Friday, I was working on a system where a session is instantiated from a stored virtual machine that produces a fresh session every time, meaning that all previous changes get lost. What I have is a batch script that I run to reinstate what I need, and I encountered another task that I wanted it to do.

Part of my work involves the creation of plain text files with the extension lst and this is getting associated with SAS instead of Notepad. While you can reassign such associations using the GUI, it would be a bonus to do it via the command line too, so the assoc and ftype commands caught my interest. The first of these associates a file with a given extension with a desired file type, while the second shows the available file types together with the associated applications that open them. The assoc command also shows all the associations that are in place when it is executed with no parameters, and the ftype command does the same for file types.

Once you have picked out a file type with the ftype command, then the assoc can be used like the following:

assoc .lst=txtfile

The above associates an extension with a file type. In this, .lst files are going to get opened by Notepad because of the txtfile association. Though it did not do what I wanted on Friday due to system lockdown, it is good to know that this is possible and that even the Windows command line supports goodies like these.

More thoughts on Windows 10

Now that I have left Windows 8.x behind me and there are a number of my machines running Windows 10, I have decided to revisit my impressions of the operating system. The first Technical Preview was something that I installed in a virtual machine, and I have been keeping an eye on how things have developed since then and intend to retain a Windows Insider installation to see what might be heading our way as Windows 10 evolves as now expected.

After elaborating on the all important upgrade process earlier, I am now moving onto other topics. While the Start Menu is a big item, there are others, as you will see below.

Start Menu

Let's start with an admission: the prototype Start Menu that we got in the initial Windows 10 Technical Preview was more to my liking. Unpinning all the tiles allowed the menu to collapse back to the sort of width that anyone familiar with Windows 7 would have liked. If there was a setting to expunge all tiles at once and produce this state, I would have been well happy.

It was later that we got to learn that Microsoft was not about to consign the Windows 8 Modern interface entirely to history, as many would have wanted. Some elements remain with us, such as a Start Menu with a mandatory area for tiles and the ability to have it display full screen. Some are live, only for this can be turned off on a tile by tile basis and unneeded ones can be removed altogether. It is even possible to uninstall most apps by right-clicking on a tile or other Start Menu entry and selecting the required option from the resulting context menu. For others, there is a command line alternative that uses PowerShell to do removals. After this pruning, things were left in such a state that I have not been moved to restore Classic Shell so far.

While the Start Menu settings used to be in the same place as those for the taskbar, they are found now in the new Settings tool. Some are in the Personalisation section, and it has its own Start subsection for setting full screen mode or highlighting of new apps, among other things. The equivalent Colours subsection is where you find other settings like assigning background colours based on those in a desktop background image, which itself is assigned in it own subsection in the Personalisation area.

Virtual Desktops

Initially, I failed to see the point in how Microsoft implemented these and favoured VirtuaWin instead. My main complaint was the taskbar showed buttons for all open apps regardless of the screen in which they are opened. However, that was changed, so your taskbar shows different buttons for each virtual desktop, just like the way that Linux and UNIX do things. Switching between desktops may not be as smooth as those yet, but the default setting is a move in the right direction, and you can change it if you like.

Cortana

Though this was presented to the world as a voice operated personal assistant like Apple's Siri, I cannot say that I am keen on such things, so I decided to work as I usually do instead. Keyboard interaction works fine, and I have neutered things to leave off web searches on Bing to use the thing much in the same way as the search box on the Windows 7 Start Menu. While it may be able to do more than that, I am more than happy to keep my workflow unchanged for now. Cortana's settings are available via its pop-up menu. Collapsing the search box to an icon to save space for your pinned and open applications is available from the Search section of the taskbar context menu (right-clicking the taskbar produces this).

Settings

In Windows 8.x, the Control Panel was not the only area for settings but remained feature complete. However, the same is not the case for Windows 10 where the new Settings panel is starting to take over from it. Though the two co-exist for now, it seems clear that Settings is where everything is headed.

Though the Personalisation section of the tool has been mentioned in relation to the Start Menu, there are plenty of others. For instance, the Privacy one is one that definitely needs reviewing, and I found myself changing a lot of the default settings in there. Naturally, there are some other sections in Settings that hardly need any attention from most of us and these include Ease of Access (accessibility), Time & language, Devices and Network & Internet. The System section has a few settings like tablet mode that may need review, while the Update & security one has backup and recovery subsections that may be of interest. The latter of these is where you find the tools for refreshing the state of the system following instability or returning to a previous Windows version (7 or 8.x) within thirty days of the upgrade.

Successfully migrating to Windows 10 on physical devices and virtual machines

While I have had preview builds of Windows 10 in various virtual machines for the most of twelve months, actually upgrading physical and virtual devices that you use for more critical work is a very different matter. Also, Windows 10 is set to be a rolling release with enhancements coming on an occasional basis, so I would like to see what comes before it hits the actual machines that I need to use. That means that a VirtualBox instance of the preview build is being retained to see what happens to that over time.

While some might call it incautious, I have taken the plunge and completely moved from Windows 8.1 to Windows 10. The first machine that I upgraded was more expendable, and success with that encouraged me to move onto others before even including a Windows 7 machine to see how that went. The 30-day restoration period allows an added degree of comfort when doing all this. The list of machines that I upgraded were a VMware VM with 32-bit Windows 8.1 Pro (itself part of a 32-bit upgrade cascade involving Windows 7 Home and Windows 8 Pro), a VirtualBox VM with 64-bit Windows 8.1, a physical PC that dual booted Linux Mint 17.2 and 64-bit Windows 8.1 and an HP Pavilion dm4 laptop (Intel Core i3 with 8 GB RAM and a 1 TB SSHD) with Windows 7.

The main issue that I uncovered with the virtual machines is that the Windows 10 update tool that is downloaded onto Windows 7 and 8.x does not accept the graphics capability on there. This is a bug because the functionality works fine on the Windows Insider builds. The solution was to download the appropriate Windows 10 ISO image for use in the ensuing upgrade. There are 32-bit and 64-bit disk images with Windows 10 and Windows 10 Pro installation files on each. My own actions used both disk images.

During the virtual machine upgrades, most of the applications that considered important were carried over from Windows 8.1 to Windows without a bother. Anyone would expect Microsoft's own software like Word, Excel and others to make the transition, but others like Adobe's Photoshop and Lightroom made it too, as did Mozilla's Firefox, albeit requiring a trip to Settings to set it as the default option for opening web pages. Less well-known desktop applications like Zinio (digital magazines) or Mapyx Quo (maps for cycling, walking and the like) were the same. Classic Shell was an exception but the Windows 10 Start Menu suffices for now anyway. Also, there was a need to reinstate Bitdefender Antivirus Plus using its new Windows 10 compatible installation file. Still, the experience was a big change from the way things used to be in the days when you used to have to reinstall nearly all your software following a Windows upgrade.

The Windows 10 update tool worked well for the Windows 8.1 PC, so no installation disks were needed. Neither was the bootloader overwritten so the Windows option needed selecting from GRUB every time there was a system reboot as part of the installation process, a temporary nuisance that was tolerated since booting into Linux Mint was preserved. Again, no critical software was lost in the process apart from Kaspersky Internet Security, which needed the Windows 10 compatible version installed, much like Bitdefender, or Epson scanning software that I found was easy to reinstall anyway. Usefully, Anquet's Outdoor Map Navigator (again used for working with walking and cycling maps) continued to function properly after the changeover.

For the Windows 7 laptop, it was much the same story, albeit with the upgrade being delivered using Windows Update. Then, the main Windows account could be connected to my Outlook account to get everything tied up with the other machines for the first time. Before the obligatory change of background picture, the browns in the one that I was using were causing interface items to appear in red, not exactly my favourite colour for application menus and the like. Now they are in blue, and all the upheaval surrounding the operating system upgrade had no effect on the Dropbox or Kaspersky installations that I had in place before it all started. If there is any irritation, it is that unpinning of application tiles from the Start Menu or turning off live tiles is not always as instantaneous as I would have liked, and that is all done now anyway.

While writing the above, I could not help thinking that more observations on Windows 10 may follow, but these will do for now. Microsoft had to get this upgrade process right, and it does appear that they have, so credit is due to them for that. So far, I have Windows 10 to be stable and will be seeing how things develop from here, especially when those new features arrive occasionally as is the promise that has been made to us users. Hopefully, that will be as painless as it needs to be to ensure trust is retained.

Three handy Linux commands, one each for navigation, system Information and upgrades

Here are some Linux commands that I encountered in a feature article in the current issue of Linux User & Developer that I had not met before:

cd -

This returns you to the previous directory where you were before with having to go back through the folder hierarchy to get there and is handy if you are jumping around a file system and any other means is far from speedy.

lsb_release -a

It can be useful to uncover what version of a distro you have from the command line and the above works for distros as diverse as Linux Mint, Debian, Fedora (it automatically installs in Fedora 22 if it is not installed already, a more advanced approach than showing you the command like in Linux Mint or Ubuntu), openSUSE and Manjaro. These days, the version may not change too often, but it still is good to uncover what you have.

yum install fedora-upgrade

This one can be run either with sudo or in a root session started with su and it is specific to Fedora. The command performs an upgrade of the Fedora distro itself, and I wonder if the functionality has been ported to the dnf command that has taken over from yum. My experiences with that in Fedora 22 so far suggest that it should be the case, though I need to check that further with the VirtualBox VM that I have created.

Controlling clearance of /tmp on Linux systems

While some may view the behaviour in a less favourable, I always have liked the way that Linux can clear its /tmp directory every time the system is restarted. The setting for this is in /etc/default/rcS and the associated line looks something like:

TMPTIME=0

The value of 0 means that the directory is flushed completely every time the system is restarted, but there are other options. A setting of -1 makes the directory behave like any other one on the system, where any file deletions are manual affairs. Using other positive integer values like 7 will specify the number of days that a file can stay in /tmp before it is removed.

What brought me to this topic was the observation that my main Linux Mint system was accumulating files in /tmp and the cause was the commenting out of the TMPTIME=0 line in /etc/default/rcS. This is not the case on Ubuntu, and using that is how I got accustomed to automatic file removal from /tmp in the first place.

All of this discussion so far has pertained to PC's where systems are turned off or restarted regularly. Things are different for servers of course and I have seen tools like tmpreaper and tmpwatch being given a mention. As if to prove that there is more than one way to do anything on Linux, shell scripting and cron remain an ever present fallback.

Restoring GRUB for dual booting of Linux and Windows

Once you end up with Windows overwriting your master boot record (MBR), you have lost the ability to use GRUB. Therefore, it would be handy to get it back if you want to start up Linux again. Though the loss of GRUB from the MBR was a deliberate act of mine, I knew that I'd have to restore GRUB to get Linux working again. So, I have been addressing the situation with a Live DVD for the likes of Ubuntu or Linux Mint. Once one of those had loaded its copy of the distribution, issuing the following command in a terminal session gets things back again:

sudo grub-install --root-directory=/media/0d104aff-ec8c-44c8-b811-92b993823444 /dev/sda

When there were error messages, I tried this one to see if I could get additional information:

sudo grub-install --root-directory=/media/0d104aff-ec8c-44c8-b811-92b993823444 /dev/sda --recheck

Also, it is possible to mount a partition on the boot drive and use that in the command to restore GRUB. Here is the required combination:

sudo mount /dev/sda1 /mnt
sudo grub-install --root-directory=/mnt /dev/sda

Either of these will get GRUB working without a hitch, and they are far more snappy than downloading Boot-Repair and using that; I was doing that for a while until a feature on triple booting appeared in an issue of Linux User & Developer that reminded me of the more readily available option. Once, there was a need to manually add an entry for Windows 7 to the GRUB menu too and, with that instated, I was able to dual-boot Ubuntu and Windows using GRUB to select which one was to start for me. Since then, I have been able to dual boot Linux Mint and Windows 8.1, with GRUB finding the latter all by itself. Since your experiences too may show this variation, it's worth bearing in mind.