Keyboard not working in Citrix Receiver for Linux – a workaround

In technological terms, this is an amazing time to be alive.
In many ways, the advances in computing over the last 20-odd years have changed the way we live.
The specific advance that concerns me in this post is the ability to securely and remotely connect from my computer at home, to the computer in the office.
These days, remote working of this nature often requires the Citrix Receiver to be installed on the client machine – i.e. the one I’m using at home.
In my case, this machine is almost certainly running a Linux OS.
This shouldn’t be a problem. After all, the Citrix Receiver is available for Linux. However, as with any application available on multiple platforms, any bugs may be specific to an individual platform.
I was reminded of this recently. Whilst my Windows and Mac using colleagues were able to use the Citrix Receiver with no problems, I found the lack of a working keyboard when connecting to my work machine something of a handicap.
What follows is a quick overview of the symptoms I experienced, together with the diagnosis of the issue. Then I go through the workaround – i.e. uninstalling the latest version of the Receiver and installing the previous version in it’s place.
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Installing SQLDeveloper and SQLCL on CentOS

As is becoming usual in the UK, the nation has been left somewhat confused in the aftermath of yet another “epoch-defining” vote.
In this case, we’ve just had a General Election campaign in which Brexit – Britain’s Exit from the EU – played a vanishingly small part. However, the result is now being interpreted as a judgement on the sort of Brexit that is demanded by the Great British Public.
It doesn’t help that, beyond prefixing the word “Brexit” with an adjective, there’s not much detail on the options that each term represents.
Up until now, we’ve had “Soft Brexit” and “Hard Brexit”, which could describe the future relationship with the EU but equally could be how you prefer your pillows.
Suddenly we’re getting Open Brexit and even Red-White-and-Blue Brexit.
It looks like the latest craze sweeping the nation is Brexit Bingo.
This involves drawing up a list of adjectives and ticking them off as they get used as a prefix for the word “Brexit”.
As an example, we could use the names of the Seven Dwarfs. After all, no-one wants a Dopey Brexit, ideally we’d like a Happy Brexit but realistically, we’re likely to end up with a Grumpy Brexit.

To take my mind off all of this wacky word-play, I’ve been playing around with CentOS again. What I’m going to cover here is how to install Oracle’s database development tools and persuade them to talk to a locally installed Express Edition database.

Specifically, I’ll be looking at :

  • Installing the appropriate Java Developer Kit (JDK)
  • Installing and configuring SQLDeveloper
  • Installing SQLCL

Sound like a Chocolate Brexit with sprinkles ? OK then… Continue reading

Resolving Hardware Issues with a Kernel Upgrade in Linux Mint

One evening recently, whilst climbing the wooden hills with netbook in hand, I encountered a cat who had decided that halfway up the stairs was a perfect place to catch forty winks.
One startled moggy later, I had become the owner of what I can only describe as…an ex-netbook.

Now, finally, I’ve managed to get a replacement (netbook, not cat).

As usual when I get a new machine, the first thing I did was to replace Windows with Linux Mint…with the immediate result being that the wireless card stopped working.

The solution ? Don’t (kernel) panic, kernel upgrade !

Support for most of the hardware out there is included in the Linux Kernel. The kernel is enhanced and released every few months. However, distributions, such as Mint, tend to stick on one kernel version for a while in order to provide a stable base on which to develop.
This means that, if Linux is not playing nicely with your Wireless card/web-cam/any other aspect of your machine’s hardware, a kernel upgrade may resolve your problem.
Obviously it’s always good to do a bit of checking to see if this might be the case.
It’s also good to have a way of putting things back as they were should the change we’re making not have the desired effect.

What I’m going to cover here is the specific issue I encountered with my new Netbook and the steps I took to figure out what kernel version might fix the problem.
I’ll then detail the kernel upgrade itself.

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Getting one of your Five-a-Day – connecting Remotely to a Raspberry Pi from Linux Mint

It’s Christmas. To mark the occasion, my son bought me a top-of-the-range computer…


Christmas has come early ! Er, hang, on…

Yes, a Raspberry Pi 2 b-spec, complete with 900 MHz Quad-core ARM processor and 1 GB RAM.

Getting it up and running was a bit more of a challenge than I had anticipated.
The Pi uses HDMI for Video output and my ageing monitor is not equipped for HDMI…


The best program on TV – NOOBS doing it’s thing.

In the end, I had to “borrow” the TV.
This arrangement was, of necessity, extremely temporary. The TV had to be back in it’s usual place ready for The Strictly-TOWIE-Dancing-Get-Me-Out-Of-Here Christmas Special, on pain of pain.
Therefore, my first Pi project was to connect to it remotely from another machine, namely, my Linux Mint Laptop.
This will enable me to run the Pi headless (i.e. without a monitor/keyboard/mouse attached to it).

I’m going to cover two different methods of connecting to the Pi.
The first is using ssh to connect to the command line.
The second is to connect remotely to the Raspbian desktop itself.

Just to avoid any confusion, I will be referring to the Raspberry Pi as “the Pi” and the machine I’m connecting from as “Mint”.
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Gits and Giggles – Getting onto Github from Mint

“Github ?” said Deb, “sounds like a chat room for grumpy old men. You should fit right in !”
To be fair, neither of us were in a particularly good mood at the time.
Deb had just been made to sit through the Rugby World Cup Final whilst my emergency backup nationality had finally born fruit.
All I said to her was that it’s nice to be able to support a real country rather than a mere principality, like Wales. Honestly, some people are so touchy.

For my part, I had just discovered that Github, based on the Git source control system written by Linus Torvalds himself, has integrated clients for Windows and Mac, but not for Linux.

No matter. If you want to interact with Github, you’ll need to have Git installed on your client machine anyway and, mine being Linux, there are a number of GUIs available for Git.

Aside from the Git documentation itself, which is extensive, there are a number of excellent guides to both Git and Github available.
Rather than re-hashing these – although I will link some of them – I’m going to look at things from a slightly different perspective.

Throughout my career, I’ve been, first and foremost, a database developer.
Way back when, choices of version control systems were rather limited. In a professional sense, I grew up with PVCS and Visual Source Safe.
Even later on, the fact that Oracle Forms and Reports were binary source code meant that the Edit-Merge paradigm of source control was something that tended not to gain traction in the Oracle Shops that I worked in.

Later on, in larger organisations, Perforce was the tool of choice, although always with the comforting P4Win ( and later P4V) front-end.

So, I’d rather like the comfort of a GUI, if only to see that the files I think I’ve checked in are actually there.

Additionally, Github uses an enhanced version of the Markdown language for text files. It would be nice to be able to preview these files before uploading them to the repository.

First things first then…. Continue reading

Keep your Database Tidy – making sure a file exists before DBMS_DATAPUMP makes a mess

There are times when I wonder whether DBMS_DATAPUMP isn’t modelled on your average teenager’s bedroom floor.
If you’ve ever tried to start an import by specifying a file that doesn’t exist ( or that DBMS_DATAPUMP can’t see) you’ll know what I mean.
The job fails, which is fair enough. However, DBMS_DATAPUMP then goes into a huff and refuses to “clean up it’s room”.
Deb has suggested that this sort of thing is also applicable to husbands.
Not that I have any idea of whose husband she’s talking about.
Anyway, you may consider it preferable to check that the export file you want to import from actually exists in the appropriate directory before risking the wrath of the temperamental datapump API.
This apparently simple check can get a bit interesting, especially if you’re on a Linux server…
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The Ping of Mild Annoyance Attack and other Linux Adventures

Sometimes, it’s the simple questions that are the most difficult to answer.
For example, how many votes does it take to get an MP elected to the UK Parliament ?
The answer actually ranges from around 20,000 to several million depending on which party said MP is standing for.
Yes, our singular electoral system has had another outing. As usual, one of the main parties has managed to win a majority of seats despite getting rather less than half of the votes cast ( in this case 37%).

Also, as has become traditional, they have claimed to have “a clear instruction from the British People”.
Whenever I hear this, can’t help feeling that the “instruction” is something along the lines of “don’t let the door hit you on the way out”.

Offering some respite from the mind-bending mathematics that is a UK General Election, I’ve recently had to ask a couple of – apparently – simple questions with regard to Linux… Continue reading