I know what I said about a post every two days but something has entered my head that seems timely. Things seem to starting up for 2008 and my getting a swathe of post ideas is only one of them. Today, Sun has bought up MySQL, the database that stores these ponderings for posterity, and Oracle has finally got its hands on Bea, the people behind the Weblogic software with which I have had an indirect brush for a lot of 2007.

The time hounoured syntax for a for loop in a UNIX script is what you see below and that is what works with the default shell in Sun’s Solaris UNIX operating system, ksh88.

for i in 1 2 3 4 5 6 7 8 9 10
do
        if [[ -d dir$i ]]
        then
            :
        else
            mkdir dir$i
        fi
done

There is a much nicer syntax supported syntax the advent of ksh93. It follows C language conventions found in all sorts of places like Java, Perl, PHP and so on. Here is an example:

for (( i=1; i<11; i++ ))
do
        if [[ -d dir$i ]]
        then
            :
        else
            mkdir dir$i
       fi
done

Contrary to appearances given by this blog, I am not exclusively a Windows user. In fact, I have sampled Linux on a number of occasions in the past and I use VMware to host a number of different distributions – my Ubuntu installation is updating itself as I write this – as I like to keep tabs on what is out there. I also retain a Windows 2000 installation for testing and have had virtual machine hosting a test release of Vista not so long ago. I also have my finger in the UNIX world with an instance of OpenSolaris, though it is currently off my system thanks to my wrecking its graphics set up. However, ZoneAlarm has been known to get ahead of itself and start blocking VMware. If you go taking a look on the web, there is no solution to this beyond a complete system refresh (format the boot drive and reinstall everything again) and I must admit that this sounds like throwing out bath, baby and bathwater together. I did find another approach though: removing ZoneAlarm and reinstalling it. This wipes all its remembered settings, including the nefarious one that conflicted with VMware in the first place. It’s amazing that no one else has considered this but it has worked for me and having to have the security software relearn everything again is much less painless than rebuilding your system.