Disable VirtualBox clock synchronization

For whatever reason you may want to disable the time/date synchronization between the VirtualBox guest system and the host OS.

See the example below to do that for an example virtual machine “myName”:

  • vmname=”myName”; printf “Disabling clock sync for vm: \”$vmname\”\n”; VBoxManage setextradata $vmname “VBoxInternal/Devices/VMMDev/0/Config/GetHostTimeDisabled” 1; VBoxManage setextradata $vmname “VBoxInternal/TM/TSCTiedToExecution” 1;

Unfortunately this is ignored when the virtual machine is shut down and then started again. The clock of the virtual machine will be forcefully synchronized to the host system clock. If you know a workaround, please post it in comments.


Using HP LaserJet 2010 printer with Linux Mint

The problem: HP LaserJet 2010 printer gets recognized by Linux Mint but fails to print.

The solution:

  • Remove all automatically installed printers
  • sudo hp-setup -i

Let it download the HP plugin and accept defaults, then print test page (you must not be root or the print will fail).

Thunderbird does not start

This may happen after a crash.

Problem: You attempt to start your Thunderbird, but its GUI window does not show. You can see it running as a process in the background, but nothing else happens.

Cause: The problem may be caused by a surviving lock file in the user profile directory.

Solution: Navigate to .thunderbird in your user directory, select the appropriate profile directory and delete or remove file .parentlock therein.


Find paragraph breaks in LibreOffice

To find paragraph breaks (i.e. the ASCII line feed character 0A hex)  in LibreOffice, use the currency symbol “$” as the search string.

Make sure to look into “Other options” and check “Regular expressions” in the “Find & Replace” dialog.


By the way, searching for “\n” and replacing it with “\n” can be done only once, as on the repeated action there will be no matches found anymore and searching for “$” must be done instead. Read some more about this bug/feature/inconsistency here.


List fonts used in PDF document

If you want to see what fonts have been used in creation of a PDF document, you can use pdffonts utility of poppler-utils package for this. Just type:

  • pdffonts yourfile.pdf

Renew Let’s Encrypt certificate

If you have no automatic certificate renewal, you may found out one day that the browser is telling you that your site is “unsafe” as the certificate has expired.

Just type at the command line:

  • letsencrypt renew

But you can also add a simple cron job for automatic renewal, for example:

  • 15 5,17 * * * /usr/bin/letsencrypt renew

Checking twice a day is recommended for the unlikely event if something happens to your certificate due to the Let’s Encrypt themselves.

If the certificate is valid and new nothing happens aside from reading the certificate locally, so you can run it as often as you want.

Mount Truecrypt volume without Truecrypt

Some of you may have some old Truecrypt volumes lying around. Truecrypt was a nice and handy utility which is not developed anymore, unfortunately. But you still can mount the volumes created by it.

One way to do it on Ubuntu:

  • sudo cryptsetup tcryptOpen myvol.tc myvol


  • myvol.tc – the file name of your volume
  • myvol – arbitrary name of the virtual disk to be created

You will be asked for a passphrase, and if you still can remember it, the volume will be mounted under /dev/mapper with the name you provided and will show up as just another disk.