No time to read through contexts? Jump to the TL;DR; section.
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
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.
No time to read through contexts? Jump to the TL;DR; section.
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:
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. More
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.
This is a spin-off of the original article found here. For the rationale on the benefits and gotchas for hibernation then refer to the original post. This post is dedicated on how to enable hibernation in Windows 7 as the instruction has changed.
Enabling the hibernation feature requires that the process be done using an administrative account on the machine.
Open an administrative command window by pressing the Window key, typing cmd, highlighting the cmd entry under the Programs group, and pressing Ctrl+Shift+Enter.
Execute the command “powercfg -h on” to enable the hibernate feature.
Open the Power Options group in the Control Panel and click the “Change plan settings” of the current active plan.
Click on the “Change advanced power settings” link in the resulting window.
Under the Sleep tree item, disable the hybrid sleep option. The hibernate option will not be available if this option is enabled.
Click on the Apply button and dismiss all succeeding dialog windows. The hibernate option should now be present on the Shutdown submenu.
At work, the Windows 7 workstation we were given came with a Trojan-esque gift: several instances of wscript.exe are running at startup and uses all available CPU processing cycles. Killing them off does not show any adverse effects (yet) but the graphical way is a bit time consuming as the machine is already slow at this point.
Below is the quickest way to snipe these instances using the lowest memory-guzzler tool in every Windows arsenal: the command line processor window. The only catch is that the wscript instances would require the kill command to be executed from an elevated command prompt as the Windows User Access Control (UAC) is active.
1. Press the Window key to bring up the startup menu.
2. In the Start menu search box, type “cmd”. The first entry highlighted is the program entry.
3. Press “Ctrl+Shift+Enter” to run the command in elevated mode. If UAC is really running, a confirmation prompt will be displayed for the command line processor.
4. Invoke the command “taskkill /im wscript.exe /f ” to kill all running instances of wscript.exe.
5. To validate if there are still instances running, run the command “tasklist | find “wscript” ” (omit the first and last double quotes). Nothing should be shown.
The exercise above can be adapted to quickly kill some errant processes without going through the task manager or resource monitor GUI clients. Be careful in what you kill for it might bite back. 🙂
[UPDATE] A colleague,Ron Emil Castro, has provided this trick on combining both in a script that will load up with administrator privileges upon startup for Vista/Win7 machines.
Create a batch script with the following code
CHOICE /N /C YN /T 15 /D Y
taskkill /im wscript.exe /f
The first command waits for 15 seconds to give the script enough time to run and the second kills it as specified in the script above.
Open the startup folder by right-clicking on the Start->All Programs->Startup item then selecting the Open option.
Create a shortcut to the batch script. Right-click on the shortcut and open the properties window. Select the “Run as Administrator” option under the Advanced section.
[UPDATE] The processes are because of an errant firewall checker script loaded by the domain policies. The alternate solution provided by the support team is to execute the C:\Windows\system32\wscript.exe binary and set the timeout to a low number (5 or 10 seconds). Use the recommendation at your own risk as this basically handicaps the execution of other scripts that would require more time than the set timeout.
Have you encountered an unfamiliar word when reading email or an article in the web? Normally this would require a quick dictionary search but Google may present an easier route. Navigate your internet browser to www.google.com and enter the following in the search box:
define:[place unfamiliar word here]
If it is popular enough, Google will present the searched definitions.
Popular and upcoming words can also be searched:
Browsers equipped with a Google search bar may offer keyboard shortcuts that will make the process easier. For Firefox, Ctrl+K will send the focus to the search bar.
[Advanced Disclaimer: Use the information in this posting at your risk]
If you want to minimize the amount of electricity used by your computer but dislike shutting down your computer because of the amount of time it need to start it up and open your applications, there is a compromise to be had if your operating system is configured properly to hibernate.
Hibernating an operating system means that all the information in the system memory (RAM to be precise) is written down as a “snapshot image” to the hard disk. The PC hardware is then turned off since the hard disk will not lose its information when powered down. When the machine is turned back on, the booting process of the operating system will look for a store snapshot image and load it back into the system memory. If this is successful, you will have your desktop at the same state as when it was hibernated. The time it needs to resume a hibernated image is relatively small compared to when booting the operating system from scratch (or what is called a cold boot).
All modern operating systems have support for hibernation but not all are enabled by default. To following steps will enable this feature in Windows XP:
Go to Start->Control Panel->Power Options.
Go to the “Hibernate” tab and ensure that the “Enable hibernation” check box is ticked. Click OK to dismiss the dialog and apply the change.
WARNING: This will reserve space on the system drive equal to the amount of RAM in your computer. If you have 2GB of RAM, 2GB of hard disk space will be set aside for hibernation.
To hibernate, shutdown the machine but select the hibernate option. The machine will be turned off automatically (if this is properly configured).
To resume the hibernated image, turn on the machine. The image will be invalidated after a successful resume.
NOTES:
– Some applications, usually those that have time-bound login sessions, do not like being hibernated.
– The space set aside for the hibernation support is different with the space allocated for the virtual memory.
– If the machine fails to resume or hangs while in the process of resuming, reboot the machine and boot into safe mode (Press F8 after the BIOS screens). Reboot the machine to invalidate the hibernate images and the machine should boot normally after.
MS Office provides a helpful function in ensuring that style consistency is easily done on the documents being created. The function is called the “Format Painter” which is part of the Standard toolbar.
If the icon is not visible (if not previously used) it can be added from the toolbar dropdown which is located at the end of the toolbar section.
How to use the Format painter:
Highlight the text (or cells in spreadsheets) containing the style that you want to copy.
Click on the “Format Painter” icon to copy the style into the painter memory.
Highlight the text (or cell) that you want to have the same format.
Format Painter loses its “memory” after every cycle so repeat steps 1-3 as you see fit. Styles can also be used in Word documents to facilitate the document formatting process.
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