the boredom of ramfree17

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There are use cases that require the secure wiping or deletion of files. There are already a lot of available utilities available in most modern distributions such as srm, swipe, etc. These however entail installing an additional package which is fine for work machines. The use case I had is to securely delete a transient file after it was generated and used in a Continuous Integration server. Installing the secure-delete package is trivial but a base Linux system already has the tool that can do the job: dd

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If the Linux VM was running at the time the host OS (Windows) hibernated then the clock in the guest VM will be left at the time of hibernation. If NTP is configured then the clock should resync gradually but most systems do not apply a big chunk of time correction by default.

If the Linux VM was configured with a VPN that implements a system-wide configuration then the DNS resolution might be unable to resolve the NTP server since the DNS of the VPN session will be unavailable. The alternate and work-around presented hinges on two things:

• The guest VM has internet access at the time it was resumed.
• The google.com domain name is already resolved and cached.

   sync-clock() {
     echo Current time before sync: `date`
     echo Current time after sync : `sudo date -s "$(wget -qSO- --max-redirect=0 google.com 2>&1 \ 
       | grep Date: | cut -d' ' -f5-8)Z"`
    }

The work-around uses the time in the google headers to provide an anchor for the correction.  This is provided as a bash function to provide user feedback if a correction was done.

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For security reasons my internet access in the office is restricted and most if not all of the sites that allow saving of data is blocked by the office proxy server. This becomes a pain if I come across some articles and sites that would be good to read later or heaven forbid something that I need. The usual route that would allow me to schedule reading the article is to save the links in my company email drafts folder, or email it to myself so I can remember to move them to my bookmarking or reminder site when I get home. This setup has been fine but being the perennial procastinator (or busy if you want to put a positive spin on it) I sometimes forget to do it immediately. The other alternative is horrible: type the url on my android device as I encounter the sites and articles. That option is as pleasing as going to the doctor for a rectal probe. I forgot to mention that my Android device doesn’t have continuous Internet by the way, which would have made my life easier and this post an academic exercise. 🙂

I have an alternative solution which works if you have a QR reader on your device. The main gist is to transfer the information to the device using a QR code. The steps follow:

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The SOA server I am currently working with had a nasty quirk on its services that I havent figured out yet on how to fix: it fails on requests with an XML comment. We use SOAPUI to trigger requests and the quirk requires most of us to strip the comments that is automatically generated by the tool. This quirk however gives me a good segue on this IT tipjar: how to leverage pattern matching to batch remove comments. This should serve as an introduction in other pattern matching applications when dealing with text/ascii content.
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Aero is a default theme in Windows Vista and Windows 7 Home Premium or better but is not enabled by default. Aero adds some nifty features like Peek (showing thumbnail previews when hovering on the open programs), Shake (shaking the window minimizes all other windows), Snap (dragging the window to the edges snaps it, useful for side by side windows organization). Aero however consumes additional CPU and GPU power but in some cases it can introduce some efficiency like repainting only the areas that are affected by window movement.

Enabling Aero requires two services to be started before they can be used: the Desktop Windows Management (uxsms), and the Themes (themes) services. Enabling them from the Control Panel->Services MMC console is fairly easy but this tip jar is about enabling them from the command line to reduce the wait and teach the basics of interacting with the Windows services using command line options.

The command are split into two categories: making sure the services are enabled, and starting them up.

sc config uxsms start= auto
net start uxsms

sc config themes start= auto
net start themes

These are administrative activities so they need to be done from within a command window that has administrative privileges. Refer to previous TipJar entries on how to do this. The “auto” parameter of the sc commands can be changed to “demand” if the services are to be start manually so as not to consume resources ?at every Windows startup. The sc invocations are only required to be done once.