The Linux Page

Help other users realize that everything is possible, especially avoiding Windows for their own personal use.

Welcome to The Linux Page


Fox Trot by Bill Amend. Click to enlarge.
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This site is a collection of my own work with Linux. Certain things are easy, others take time to decipher and if I ever need to repeat the work (which usually happens!), then I need to remember everything by memory or... have a site with all the steps taken and to take again.

The following are my most recent posts:

Often, when you use LEFT JOIN, you will have one table and one comparison.

Whenever you need more than one comparison, they must be put between parenthesis, otherwise you get that silly error saying: LEFT JOIN are not supported.

So you need to write something like this:

SELECT *

FROM table

LEFT JOIN other

ON (table.f1 = other.f1 AND table.f2 = other.f2)

WHERE table.f3 = 'something'

As I was writing a report using VBA in MS-Access, I needed to get a name from a table. Yet, once in a while, that name does not exist in that table (for good reasons) and yet I'd like a more human name than the default number that you otherwise get... The result was a need for two LEFT JOIN in my SQL command.

  1. Using the result

I have three text boxes in my form:

(a) The one that the user sees with the valid result, it actually includes a simple VBA script:

In MS-Access, you can select a special value for your combo boxes called:

"Find a record on my form based on the value I selected in my combo box"

In older versions of MS-Access, all you had to do is select the option and be done with it. However, the option would have no effect if the form was not properly assigned a source query.

In order to paliate to that problem, Microsoft decided to check the current form status and, if unlinked, hide the option altogether so you cannot make a mistake.

The problem is that for many people the train of thought was not automatically that way.

Have you seen animated icons in your tabs? This has been working for a while, with IE and FF and Co.

All you have to do is create an animated GIF file as your "favicon.ico", and it is better to name it .gif, by the way.

Because icons can now be pretty much any image format, not just .ico

And if you need some favicon for your site, check this one out: http://www.favicon.cc

Many of these are free!

Today I connected on PayPal to check out a sale and got a message from my system saying that a certificate could not be verified because it had a PayPal URL but pointed to geo-trinity.com.

You can see the message below:

You have attempted to establish a connection with "ekkef42kcpmrf2r3.stats.paypal.com". However, the security certificate presented belongs to "*.geo-trinity.com". It is possible, though unlikely, that someone may be trying to intercept your communication with the web site.

If you suspect the certificate shown does not belong to ...

Wired Train Station, Ready for Your Next Trip?

A week or so ago we updated our Ubuntu server to Intrepid and ran in a problem with tripwire that showed up like this:

tripwire -m u -r <report-file>
### Error: Keyfile Read/Write error.
### /etc/tripwire/site.key
### Exiting...

We tried to renew the key file with the following:

twadmin -m G -S /etc/tripwire/site.key

and it did not make any difference (other than the key file had a new date).

The permissions looked right too (root, u+rw only).

When trying to regenerate the .pol or .cfg we got the same error:

twadmin -m P -p /etc/tripwire/tw.pol ...

It happens all the time. You create two or three option groups and start adding radio buttons.

Then you write some VBA code attached to each button and/or their option group.

And at some point in the development you notice that one was put in the wrong option group.

Just deleting the option and creating a new one is not a good option because then you have to make totally sure you have the right setup and that can take some time to review.

Instead, you can move a radio button from one option group to another by following these steps:

Symptoms

  1. My checkbox does not have an AfterUpdate event
  2. When running, I cannot de-select that check box once selected

Discovery Process to Solution

In MS-Access, you often want to run an action after the user changed something in a form.

How it works

The at command is often used to start a process at a later time. It can run any script at a specified date and time.

For instance, if you want the computer to send you a signal in one hour, use something like:

cat signal | at -q z now + 60 minutes

Assuming that the file named signal contains the commands necessary to generate the signal. Then in 60 minutes, the script will be execute and the signal will be heard or shown.

Lately, I noticed that I always had a clamav.inoc.net connection. I was wondering why... I did install clamav but I did not recall changing anything in Apache where I'd get requests from the outside that would look like clamav.

The fact is I also installed freshclam. By default, that gives you a line like this in your netstat -a64 listing:

    tcp   383     0 halk:38272       clamav.inoc.net:www     CLOSE_WAIT

Most of the time you won't catch it when it is still connected and sending/receiving data. The deamon that accepts the connections is freshclam and it will save the new data ...

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