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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:

Skip Postgrey test with a Postfix restriction map

By default, when postfix is installed with postgrey, all the emails that are not blocked by some other means are all passed to postgrey.

What if you have a customer who doesn't want to wait forever to get his/her emails?

Well... you need to bypass postgrey (and good luck to him/her in regard to heavy spamming...)

The setup requires two additional entries as defined here:

# in main.cf
smtpd_restriction_classes = permissive
permissive = permit

Here we define a new class called "permissive" (which is case sensitive!) and that we will use in the restriction access file.

I had a problem with jQuery and was wondering what could be wrong. Looking around for a solution, it was clear that Internet Explorer is the problem. Not the other way around (As usual.) The thing is that the function works, just not in realtime.

So... I have a Terms and Conditions flag, when you click it, I want to enable the Submit button in the form (by default the button is disabled.)

So I have a function something like this:

var valid = function check_valid() {
  // compute valid
  var valid = ...;
  // assume valid === true if button should be enabled
  ...

Try to recompile Qt with Pavel's instructrions...

I did not encounter much problems, although the examples failed. It looks like jom would be the problem as some people reported not having problems following the same steps, but using nmake instead of jom.

The instructions go like this: [Update: the links below all stopped working.]

Visual C++ 2010 contains all necessary SDKs for Qt compilation. However if you plan to use Qt with Phonon you need to install additional software from Qt for Windows Requirements list.
Download and extract Qt 4.7.4 Sources. (Or Qt ...

As I was looking for a COFF Browser today (a tool that would show me the internals of a DLL or EXE file) I stumbled upon a page talking about Assembly Language and the GoAsm tools.

The page is here: [page was removed]

Interestingly enough, he has a link to an advanced assembler called GoAsm. This is specifically for MS-Windows and they do not release the source code of the assembler (at least, not that I can see...) But it is still interesting to see such tool suite around. 8-)

It has always been weird to me to see that the delete operator was not actually going to call all the destructor on objects. That is, if you create a class B that derives from a class A, deleting an object when cast to A does not (by default) call the destructor defined in class B.

The result is that ALL classes should define their destructor as virtual. This doesn't make sense because you shouldn't have to have a virtual table in all your objects just for the destructor to work right. On the other hand, class A has no way to know that it will be derived by class B so its destructor

Virtual Box Bridging

I have a computer with Ubuntu 11.04 (the host) on which I installed a version of Ubuntu 11.10 (the guest) using QEMU. Both are 64bit on an i5 quad.

What I'm trying to do is allow the host to access the guest via a br0 bridge and possibly using all static addresses so they don't change on me (there still seem to be some DHCP going on the guest side and maybe that's part of the problem.)

When I start qemu with nic/user, it works as expected (well... somehow the nameserver 10.0.2.3 fails now... since I installed my br0 bridge, but I can fix the ...

local delete, incoming edit upon update

Today I tried to move an SVN folder to another.

In my first attempt, I tried to copy the folder to a sub-folder that was not in SVN. The result is that the move failed, but nothing seemed to change in the SVN environment.

So I tried again, this time making sure that the destination folder would be an SVN folder.

The second time, however, it failed. The move instruction reported a conflict... Then the svn commit would not work. The SVN system was thinking that I changed something with the first svn mv as the failure did not clear the conflict.

svn mv a tmp/a-1.x        # fails saying tmp/ ...

Handling Certificate under Linux

The following are some commands I use to read certificate and otherwise work with OpenSSL which I otherwise find somewhat difficult to use.

To read a certificate, you use the -text and -noout to get the result in stdout. Use the -in to specify the

openssl x509 -text -noout -in server.pem

The first parameter is the type of of key. I'm not sure where you should use what, but in general you can use x509 (csr file) and rsa (rsa files). I'm not too sure why they cannot just detect what's what...

Assuming you were able to install your .pem certificate and private key on your HTTP ...

When you use Ubuntu X11 you at times want to start an application as Root.

In your console you'd use the sudo tool which gives the command temporary super-user powers.

sudo my-command

In Ubuntu Gnome you can do the same using the gksu command. So add an icon, enter the usual information, and for your command, add gksu in front of it. When clicked, you'll first get a prompt asking you your sudo password, then the command is executed as if the root user had started it.

gksu faxanwer ttyS0

Ever wondered whether you could ask bash auto-complete to ignore some of your files?

You can with the FIGNORE feature and the bind feature:

export FIGNORE=CVS:\~:.o:.svn
bind 'set match-hidden-files off'

You had one or both of these lines to your .bashrc file and then the .svn and CVS folders won't be used anymore! Add all the extensions you don't like in there and you'll feel better soon!

Note: The \ in front of ~ is to avoid the bash expansion of that character.

Unfreeze your Mouse when it Froze

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Virtual Box Bridging