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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:

Copy files between a guest (virtualbox) and the host

Brdige between your Host and Guest computers

I use VirtualBox and had a problem with copying files between my host (main computer on which you boot your computer) and the guests (virtual computer that you run on your host).

The fact is that it is all explained right here:

https://www.virtualbox.org/manual/ch04.html

There are a few steps as follow.

Using scp

Here, I have an example of GParted where I could not install the VirtualBox tools as mentioned below. This is mainly a matter if setting up an SSH server and allowing connections for a given user.

Install the VirtualBox Tools

Install the Virtual Box Tools ...

tripwire --init not saving the database

Beetle — tripwire includes a bug!

Error: File seek failed

I ran in a problem with tripwire, it did not want to generate the <hostname>.twd file under /var/lib/tripwire. You know that the file is missing because you receive emails (reports) by tripwire that the file is missing.

I could see that because it reports, once a day, whether tripwire ran sucessfully or not. It was not and the main error was: the tripwire database does exist which is actually shown as:

### Error: File could not be opened.
### Filename: /var/lib/tripwire/<hostname>.twd
### No such file or directory
### Exiting...

That, in ...

As we are upgrading our server to jump from version 12.04 to 13.04, we encounter a few problems.

Two with Postfix, first the Postgrey port has changed. It was 60000 before, now it is 10023. Don't ask me... Anyway, that was the easy one.

The other problem was a relay error. I could send emails all I wanted, but not my partner who does not show his server as part of our Made to Order Software Corp. network. Relay is why a computer allows emails from server X to be sent to server Y through server Z. You are server Z, that's the relay.

The fact is that if you can log in your account on ...

As I was moving my Drupal 6.x websites from an old server to a new one, I decided to make use of the newest PostgreSQL database system because over time I've notice quite a few things that got fixed and thus it is a lot better! (It is not as exciting as moving from 7.4 to 8.0 way back then, but still!)

Doing so, my Drupal site started showing WSOD (White Screens Of Death). Looking at the errors in my apache2 logs, I noticed that the error was in link with the cache. Looking closer, I could see that the cache (one of the only table doing so) makes use of the %b flag which means blob. It ...

As I am working on wpkg, a tool to build and manage advanced packages, I encounter problems running MS-DOS scripts. I am not the strongest in that realm. I have been working with Unix scripts for a little over 15 years and MS-DOS scripts are so limiting...

Anyway, to run a batch file, you need to write a script in a file that ends with .bat and to make sure it gets run properly, you want to run it using the %COMSPEC% command using the /c flag.

If parameters to the command include spaces, you want to place those parameters between double quotes. Although some commands are capable of ...

As I was working on a project in MS-Access, I ran in a problem with this error which meant close to nothing, at least nothing to do with what I was working on.

The truth was that I had made changes in a parent form and the sub-form Load function would fail with that error. After a while I finally thought that the problem was probably with the fact that the parent was not compiling.

I used the Debug feature to compile everything and fixed the couple of errors I had to fix the problem. What the error in itself was is most certainly not relevant, although the two reasons for the mix up were ...

Today I ran in a problem with cmake which was to very simply select /MT instead of /MD for a small set of projects. The problem is that so far this feature was at least on a per directory basis. Since the exact same directory is used to build the dynamic (DLL) and static (.lib) libraries, having two directories is not exactly an option here.

set ( CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} /MT" )
set ( CMAKE_C_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} /MT" )
set ( CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_RELEASE} /MTd" )
set ( CMAKE_C_FLAGS_DEBUG ...

When running a process under MS-Windows, it is at times rather difficult to find a problem caused by some slowness in your code, especially when it is not expected to be slow.and you do not get any kind of feedback from your software outside of the slowness itself.

When that happens a good way to find the problem is to use a profiler. Under MS-Windows, you have quite a few choices, but in most cases I've seen rather complicated solutions. Today I was told to check in Very Sleepy which I downloaded very quickly, installed very quickly, and ran very quickly., Also it did not give me the ...

In the last few days I've been trying to find the reason for a slowness in one very specific case in a software. It looks like it crashes and since it includes many try/catch with (...) it certainly captures the fact, but contrary to what it is expected to do, this one does not get logged! In any event, I wanted to prove that the area where we first were looking was not affected, and sure enough it was not. The problem is somewhere else. However, to prove that I needed to have a way to log milli-seconds because things happen very fast and a 1 second decimation is definitively not enough.

I've been looking around every now and then to try to understand how I could create a server that replies on the correct Ethernet port.

The idea is simple, we have very powerful servers that can handle many requests, more requests that one Ethernet port can handle. In other words, we could have 2, 3, 4, probably even 10 Ethernet connections (it really depends on your application, of course: how much RAM you need, how much processing is necessary for each access, etc.)

The solution is to use the ip command line which allows us to add default gateways for each ethernet card based on the ...

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Using scp

Install the VirtualBox Tools

Error: File seek failed