Adventures & experiences in contemporary technology
Recently, I noticed that the disk in my WD My Cloud NAS was active all the time so it reminded me of another time when this happened. Then, I needed to activate the SSH service on the device and log in as root with the password welc0me. That default password was changed before doing anything else. Since the device runs on Debian Linux, that was a simple case of using the passwd command and following the prompts. One word of caution is in order since only root can be used for SSH connections to a WD My Cloud NAS and any other user that you set up will not have these privileges.
The cause of all the activity was two services: wdmcserverd and wdphotodbmergerd. One way to halt their actions is to stop the services using these commands:
/etc/init.d/wdmcserverd stop
/etc/init.d/wdphotodbmergerd stop
The above act only works until the next system restart so these command should make for a more persistent disabling of the culprits:
update-rc.d -f wdmcserverd remove
update-rc.d -f wdphotodbmergerd remove
If all else fails, removing executable privileges from the normally executable files that the services need will work and it is a solution that I have tried with success between system updates:
cd /etc/init.d
chmod 644 wdmcserverd
reboot
Between all of these, it should be possible to have you WD My Cloud NAS go into power saving mode as it should though turning off additional services such as DLNA may be what some need to do. Having turned off these already, I only needed to disable the photo thumbnail services that were the cause of my machine’s troubles.
Having moved beyond the slow response and larger memory footprint of Firefox ESR, I am using Firefox Developer Edition in its place even if it means living without a status bar at the bottom of the window. Hopefully, someone will create an equivalent of the old add-on bar extensions that worked before the release of Firefox Quantum.
Firefox Developer Edition may be pre-release software with some extras for web developers like being able to to drill into an HTML element and see its properties but I am finding it stable enough for everyday use. It is speedy too, which helps, and it has its own profile so it can co-exist on the same machine as regular releases of Firefox like its ESR and Quantum variants.
Installation takes a little added effort though and there are various options available. My chosen method involved Ubuntu Make. Installing this involves setting up a new PPA as the first step and the following commands added the software to my system:
sudo add-apt-repository ppa:ubuntu-desktop/ubuntu-make
sudo apt-get update
sudo apt-get install ubuntu-make
With the above completed, it was simple to install Firefox Developer edition using the following command:
umake web firefox-dev
Where things got a bit more complicated was getting entries added to the Cinnamon Menu and Docky. The former was sorted using the cinnamon-menu-editor command but the latter needed some tinkering with my firefox-developer.desktop file found in .local/share/applications/ within my user area to get the right icon shown. Discovering this took me into .gconf/apps/docky-2/Docky/Interface/DockPreferences/%gconf.xml where I found the location of the firefox-developer.desktop that needed changing. Once this was completed, there was nothing else to do from the operating system side.
Within Firefox itself, I opted to turn off warnings about password logins on non-https websites by going to about:config using the address bar, then looking for security.insecure_field_warning.contextual.enabled and changing its value from True to False. Some may decry this but there are some local websites on my machine that need attention at times. Otherwise, Firefox is installed with user access so I can update it as if it were a Windows or MacOS application and that is useful given that there are frequent new releases. All is going as I want it so far.
This is how I got around problem that occurred when I was updating a virtualised Ubuntu 16.04 instance that I have. My usual way to do this is using apt-get or apt from the command line and the process halted because a pre-removal script for the upgrade of avahi-dnsconf failed. The cause was its not disabling the avahi daemon beforehand so I need to execute the following command before repeating the operation:
sudo systemctl disable avahi-daemon
Once the upgrade had completed, then it was time to re-enable the service using the following command:
sudo systemctl enable avahi-daemon
Ideally, this would completed without such manual intervention and there is a bug report for the unexpected behaviour. Hopefully, it will be sorted soon but these steps will fix things for now.
There was a time when the only recommended way to upgrade Linux Mint from one version to another was to do a fresh installation with back-ups of data and a list of the installed applications created from a special tool.
Even so, it never stopped me doing my own style of in situ upgrade though some might see that as a risky option. More often than not, that actually worked without causing major problems in a time when Linux Mint releases were more tightly tied to Ubuntu’s own six-monthly cycle.
In recent years, Linux Mint’s releases have kept in line with Ubuntu’s Long Term Support (LTS) editions instead. That means that any major change comes only every two years with minor releases in between those. The latter are delivered through Linux Mint’s Update Manager so the process is a simple one to implement. Still, upgrades are not forced on you so it is left to your discretion as to when you need to upgrade since all main and interim versions get the same extended level of support. In fact, the recommendation is not to upgrade at all unless something is broken on your own installation.
For a number of reasons, I stuck with that advice by sticking on my main machine with Linux Mint 17.3 instead of upgrading to Linux Mint 18. The fact that I broke things on another machine using an older method of upgrading provided even more encouragement.
However, I subsequently discovered another means of upgrading between major versions of Linux Mint that had some endorsement from the project. There still are warnings about testing a live DVD version of Linux Mint on your PC first and backing up your data beforehand. Another task is ensuring that you are upgraded from a fully up to data Linux Mint 17.3 installation.
When you are ready, you can install mintupgrade using the following command:
sudo apt-get install mintupgrade
When that is installed, there is a sequence of tasks that you need to do. The first of these is to simulate an upgrade to test for the appearance of untoward messages and resolve them. Repeating any checking until all is well gets a recommendation. The command is as follows:
mintupgrade check
Once you are happy that the system is ready, the next step is to download the updated packages so they are on your machine ahead of their installation. Only then should you begin the upgrade process. The two commands that you need to execute are below:
mintupgrade download
mintupgrade upgrade
Once these have completed, you can restart your system. In my case the whole process worked well with only my PHP installation needing attention. A clash between different versions of the scripting interpretor was addressed by removing the older one since PHP 7 is best kept for sake of testing. Beyond that, a reinstallation of VMware Player and the move from version 18 to version 18.1, there hardly was anything more to do and there was next to no real disruption. That is just as well since I depend heavily on my main PC these days. The backup option of a full installation would have left me clearing up things for a few days afterwards since I use a bespoke selection of software.
My usual method for copying a directory tree without any of the files in there involves the use of the Windows commands line XCOPY and the command takes the following form:
xcopy /t /e <source> <destination>
The /t switch tells XCOPY to copy only the directory structure while the /e one tells it to include empty directories too. Substituting /s for /e would ensure that only non-empty directories are copied. <source> and <destination> are the directory paths that you want to use and need to be enclosed in quotes if you have a space in a directory name.
There is one drawback to this approach that I have discovered. When you have long directory paths, messages about there being insufficient memory are issued and the command fails. The limitation has nothing to do with the machine that you are using but is a limitation of XCOPY itself.
After discovering that, I got to checking if ROBOCOPY can do the same thing without the same file path length limitation because I did not have the liberty of shortening folder names to get the whole path within the length expected by XCOPY. The following is the form of the command that I found did what I needed:
robocopy <source> <destination> /e /xf *.* /r:0 /w:0 /fft
Again, <source> and <destination> are the directory paths that you want to use and need to be enclosed in quotes if you have a space in a directory name. The /e switch copies all subdirectories and not just non-empty ones. Then, the xf *.* portion excludes all files from the copying process. The remaining options are added to help with getting around access issues and to try copy only those directories that do not exist in the destination location. The /ftt switch was added to address the latter by causing ROBOCOPY to assume FAT file times. To get around the folder permission delays, the /r:0 switch was added to stop any operation being retried with /w:0 setting wait times to 0 seconds. All this was enough to achieve what I wanted and I am keeping it on file for my future reference as well as sharing it with you.
BASH is a command-line interpretor that is commonly used by Linux and UNIX operating systems. Chances are that you will find find yourself in a BASH session if you start up a terminal emulator in many of these though there are others like KSH and SSH too.
BASH comes with its own configuration files and one of these is located in your own home directory, .bashrc. Among other things, it can become a place to store command shortcuts or aliases. Here is an example:
alias us=’sudo apt-get update && sudo apt-get upgrade’
Such a definition needs there to be no spaces around the equals sign and the actual command to be declared in single quotes. Doing anything other than this will not work as I have found. Also, there are times when you want to update or add one of these and use it without shutting down a terminal emulator and restarting it.
To reload the .bashrc file to use the updates contained in there, one of the following commands can be issued:
source ~/.bashrc
. ~/.bashrc
Both will read the file and execute its contents so you get those updates made available so you can continue what you are doing. There appears to be a tendency for this kind of thing in the world of Linux and UNIX because it also applies to remounting drives after a change to /etc/fstab and restarting system services like Apache, MySQL or Nginx. The command for the former is below:
sudo mount -a
Often, the means for applying the sorts of in-situ changes that you make are simple ones too and anything that avoids system reboots has to be good since you have less work interruptions.
Recently, I had a situation where my the VDI files for my Windows 10 virtual machine expanded in size all of a sudden and I needed to reduce them. My downloading maps for use with RouteBuddy may have been the cause so I moved the ISO installation files onto the underlying Linux Mint drives. With that space, I then set to uncovering how to compact the virtual disk file and the Sysinternals sdelete tool was recommended for clearing unused space. After downloading, I set it to work in a PowerShell session running on the guest operating system from its directory using the following command:
.\sdelete -z [drive letter designation; E: is an example]
From the command prompt, the following should do:
sdelete -z [drive letter designation; E: is an example]
Once, that had completed, I shut down the VM and executed a command like the following from a bash terminal session:
VBoxManage modifyhd [file location/file name].vdi --compact
Where there was space to release, VDI files were reduced in size to return more disk space. More could be done so I will look into the Windows 10 drives to see what else needs to be moved out of them.
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 in order 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.
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 but it seemed a non-ideal solution so I looked further. It was then that I found that manually resetting a system’s Windows Updates components helped others so 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.
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 in Windows until I came across the mklink command, which came with the launch of Windows Vista at the start of 2007. While the then new feature may not be an obvious to most of us, it does does that Windows did incorporate a feature from UNIX and Linux well before the advent of virtual desktops on 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.