Twiddling with tar – Differential backups on Linux

When I first mentioned the title of this post to my girlfriend, she misheard and thought there was an extra “t” at the end.
One hasty explanation later I have avoided banishment to the shed. All of which is mildly ironic as the tar command comes with a whole alphabet of options, many of which are about to get used here.

As it’s name suggests, the venerable tar command ( Tape ARchive) has it’s roots back in the time when computers were the size of a small semi in Dagenham and punch cards and tapes were the acme of the Programmer’s art.

Now I’m going to use it for backing up data on my assorted Ubuntu machines.
What I want to do here is :

  • work out how much data I need to backup
  • create a full backup of all of my data
  • make sure I know what files have been backed up
  • test the restore of a file from the backup
  • make subsequent incremental backups

In the course of this odyssey, we will discover that du has a human face and that tar has a bit of a yellow streak.
There are several things that can go horribly wrong when playing around with tar, so I’m going to test everything on a small subset of files…that I have safely stored elsewhere.
Speaking of which… Continue reading

Apache, Aliases and Zenity on Ubuntu – how to control your ego

It’s the weekend. My girlfriend is staring at the screen in ferocious concentration as she does battle with her latest essay plan for the Masters she’s studying for.
Evicted from the desk and consigned to a dark corner, I’m trying to find some diverting, productive and, above all, quiet, way to amuse myself. As any parent will know, when the kids are quiet, it usually means they’re up to something… Continue reading

Configuring OPAL on Ubuntu Desktop – without the Oracle Instant Client

Many years ago, my son had more-or-less worked out that Santa was a myth, but hadn’t wanted to say anything for fear of decreasing the number of Christmas presents he might get.
Taking my parental duties as seriously as I do, I took him to one side and explained the truth…
After Return of the Jedi, Darth Vader fell upon hard-times. There weren’t many film roles about for Dark Lords of the Sith. Eventually he decided upon a change of career and bought the round off Father Christmas, who was retiring.
Obviously, Darth Vader has a rather more direct approach to naughty children and if my son didn’t behave himself, not only would he not get any presents but he might get something cut off.
It is for this reason that Simon has the Darth Vader theme as the ringtone on his phone for when I call.

All of which has at best, a tenuous link to the theme of this post ( but I thought it was time to get into the festive spirit).

Following on from last week’s introduction to PL/SQL, some people have asked about using PL/SQL a web application (without all that mucky APEX stuff). In order to start working up some examples of this, I thought it would be a good idea to use PHP as a front-end. Yes – Oracle’s version of a LAMP system – Oracle, PHP, Apache, Linux (OPAL). After all, how hard could it be ?
Continue reading

Zen and the Art of Shell Scripting

You know what it’s like with a little kid at his birthday party. They get all excited, eat far too many sugary foods and then run around behaving badly.
Oracle Openworld has ended for another year, and not a minute too soon. Hopefully, Larry will have an early night and stop being so excitable and upsetting all those jolly nice open source types he had round.
Meanwhile, in the comparative calm of the backwater that is this blog, I’ve been getting all Zen. Well, zenity, to be precise. Yep, I’ve decided that some my batch scripts needed to get all GUI with Gnome and zenity looks to be the tool to do it.
What follows is an account of my first steps with zenity followed by a demonstration of some of it’s capabilities. Continue reading

Ripping Yarns – Music, Samba, Ubuntu and Various Discworld Characters

Yes, I know this is supposed to be a blog about Oracle stuff. It’s just that, well, Larry’s been busy this week upsetting large chunks of the Open Source Community – MySQL; OpenSolaris; even James Gosling has had T-shirts printed up urging Oracle to “Let Java Go”. Suffice to say that, given all of this furore, I’ve concluded that I could do with improving my Open Source Karma a bit.
Fortunately, I’ve been busy this week, loading all of my newly inherited music collection onto by Ubuntu Server to enable playback from any other machine on the network. What follows is an account of my adventures.
It was a simple plan – rip all of the CDs to an existing Samba Share on the server and then find software that can read the format and allow playback on both Windows and Linux. Continue reading

Oracle Client on Ubuntu – Installation and Configuration

Having obtained a sick laptop and nursed it back to health ( i.e. installed Ubuntu 10.04), I’ve decided to do something a bit more useful with it.
I want to be able to connect to the Oracle 11g database on my server. This means, installing an Oracle Client.
I’ll be using the machine mainly for SQL*Plus ( although I may well be installing SQLDeveloper shortly). Therefore, rather than mess about downloading the client directly from the Oracle site, I’m going to use the XE client, which is available in the Oracle supplied apt package repository.
NOTE – if you simply must have the full Oracle Instant Client, then you can find details of that installation here.
Continue reading

Getting the Quiz Machine to Pay Out – talking to your database from a shell script

I was in the pub the other day with my mate Simon. It’s surprising just how many of my posts have their genesis in such a setting. For the benefit of any prospective employers ( and my Mum), I put this down to the company and the mental stimulation of working out just exactly how you collect your winnings from the Quiz Machine.
For anyone who does not have first-hand experience of English Pub Quiz machines, the trick is either to a) get the barman to pay you from the till or b) have about your person a rather large hammer.

Fortunately, the hammer wasn’t required on this particular occasion, which is just as well as neither of us had brought one ( it’s not really that kind of pub). The reason for our lack of success eventually became apparent. After a conversational odyssey through the Bedfordshire countryside (the vicissitudes of Luton Town) via Table Mountain (England’s prospects for the World Cup), Simon – definitely the brains of the operation in Quiz Machine terms – confessed to wrestling with one of those perennial problems that are an occupational hazard of the Database Specialist’s art.

Yes, as well as being a bit of a whizz on the Science and Nature stuff, Simon is a long-time Teradata expert. Continue reading