Definite's Extractor

My findings on Life, Linux, Open Source, and so on.

Category Archives: *nix

How to get the active title of an X program

I have scripts that will utilise the SFDC case number, but why type it manually when the computer can do it?

Firstly, you need to have xdotool installed, for RHEL or CentOS Stream, it is in EPEL. I have tried xprop and xwininfo, but they do not accept search with WM_Class

Secondly, get the WM_Class of the X program, usually it is just the program name. If you are unsure, open that X program, then run xprog and click at the X program, then search WM_CLASS amongst the output.

Thirdly, for X program that has multiple tabs, make sure you activate the tab you want.

Now, to get the active title of firefox:

for i in $(xdotool search --onlyvisible --class firefox); do xdotool getwindowname $i; done

Two titles will be shown like:

The actual title

For me, I am only interest in the number which are in the beginning of the title, so my command is:

for i in $(xdotool search --onlyvisible --class firefox); do xdotool getwindowname $i; done | sed -rne '/^[0-9]+/ s/^([0-9]+).*$/\1/p'

Barrier/Synergy installation on EL8

I have packaged barrier and synergy a while ago. A user stated that he cannot install it because it misses dependency: avahi-compat-libdns_sd

For RHEL 8, it is in channel codeready-builder-for-rhel-8-x86_64-rpms

To enable it, runs
subscription-manager repos --enable codeready-builder-for-rhel-8-x86_64-rpms

For CentOS Stream 8, it is in repository powertools

To enable it, runs
sudo yum-config-manager --enablerepo powertools

Barrier (Synergy) with Wacom Intuos BT M

I am looking for a more ergonomic pointing device. Thus, I borrow my daughter’s Wacom Intuos BT M drawing tablet a try.

Fedora 33 Gnome seems to recognize it out of the box, and the gnome-control-center Wacom interface show it properly. With RHEL 8, it also works as a mouse, but for Gnome to see it, I needed to install the following:

yum -y install libwacom

I mainly use KDE, so I also install

yum -y install kcm_wacomtablet

Gnome did not have the UI to bind the tablet button to mouse button like Mouse button 4 (Scroll Up), nor does it handle key combo binding properly. For example, Ctrl-Win-Left is recognized as Primary-Super-Hyper-Left; KDE, however, does support Mouse button 4~7 so I bind inner left tablet button as button 5 and inner right tablet button as button 4.

I use barrier, a keyboard/mouse sharing utility intensively. So I would also like to see how barrier handles Wacom. Unfortunately, with absolute position mode (the default), the pointer insisted it needed to be in the left edge of the client, I need to use barrier switchInDirection keyboard short keyboard to get away.

I also tried related position mode which make the tablet work more like a giant touchpad. It kinda of work, as the pointer in client act normally. However, that mode is very unpleasant to use, as I need to fully away the distant between stylus and tablet. Basically:

State 1: Stylus touch tablet: Mouse Left button click
State 2: Stylus hover tablet: Mouse move
State 3: Stylus leave tablet: Mouse No action

Switching between State 2 and State 3 is required for related position to work, that is unpleasant.

I tried USB on server, and BT on client as well, but Intuos only support single connection, that is, you have to disconnect USB to use BT, so no single-button-toggle target computers. 😦

Verdict: I would not a recommended Wacom over Barrier/Synergy setup, unless You are OK with relative position mode.

HOWTO: Configure Time (NTP) for Windows Server 2016 Using Command Line (cmd)

This is aimed to be complete steps for configuring the time service (NTP) for Windows Sever 2016. This is especially useful should you want to setup your own Active Directory Domain Controller (ADDC).

0. Networking Check

Ensure you can reach the NTP server. Assuming you are using :


1. Set the Time Zone

By default, windows just assume a time zone and show you the system clock. However, the default time zone is not necessary correct.

1.1. Check the Current Timezone

tzutil /g

1.2 (Optional) Query Available Time Zone

tzutil /l

1.3 (Optional) Set Time Zone

tzutil /s "E. Australia Standard Time"

2. Set the w32time service

2.1 Configure NTP Service

w32tm /config /manualpeerlist:"" /syncfromflags:manual /reliable:no /update

2.2 Confirm that NTP Configuration

List the peers

w32tm /query /peers
The result looks like:
#Peers 3
State: Active
Time Remaining: 123.4567890s
Mode: 1 (Symmetric Active)

List the time source

w32tm /query /source
The result looks like:

2.3 Resync

w32tm /resync
The result looks like:
Sending resync command to local computer
The command completed successfully.

2.4 Indicate that NTP service is now reliable

w32tm /config /reliable:yes /update

2.5 Confirm status

w32tm /query /status
The result should looks like:
Leap Indicator: 0(no warning)

This should be it.

Build in epel8 branch with fedpkg

This article assumes you have commit right to the package, but you don’t have the epel8 branch in

  1. PKG=<YourPackage>
  2. fedpkg clone $PKG # if you have not done this
  3. cd $PKG # if you have not done this
  4. git branch epel8
  5. # Make the branch work with epel8
  6. git commit
  7. git push –set-upstream origin epel8
  8. fedpkg build
  9. Go to bodhi and create -> New update


The “Proper” Way to Use Microsoft Word Master Document

Long story short, don’t use it, use field IncludeText instead.

As a DevOps/software engineer, I prefer to keep my files (even the MS word documents) consistent and synchronised.

I am looking for jobs and sending my resume to two kinds of organisations: public sector and industry. Public sector jobs usually require referees, while in industry, referees are not mandatory. So I have two types of resumes: with or without referees.

Why don’t I just use the one with referees? Some international recruiters are not aware of time differences and just call you in the most inconvenient time. I have received a call at 4:30 am, when all of my family are sleeping. So that’s why I am reluctant to include referees in my industry resume.

To keep both branches in sync, I though the master document was a good idea, until I saved and opened the master document, and I see mess, just as describe in Why Master Documents corrupt. And I saw an interesting quote:

There are two kinds of Master Documents: Those that are corrupt and those that will be corrupt soon. – John McGhie

I have also tried auto text in “building block”. The main problem of that is: I have hard time to locate them. I cannot remember whether I save it in or . When I need to update contacts several months later, I will probably forget they are in auto text.

Eventually, I found that the field IncludeText actually helps. But there are CATCHES:

  1. The insert field command is also not easy to find in UI. Search “Insert field” is more reliable. (The search field is at “Tell me what you want to do”)
  2. You need to manually input the filename, there are NO file dialog for you to choose.
  3. If the document is on OneDrive, the full path in local drive WON’T WORK. You need related path to OneDrive\Documents. For example. If the sub document, referees.docx is in the directory OneDrive\Job and your main document is also at OneDrive\Job, you need to insert ../Job/referees.doc to the field IncludeText in your main document.
  4. URLs in sub documents need to be well-formatted. In other words, for email addresses, WON’T work, you need
  5. Even if you do enter the correct URLs, MS Word like to show them as it pleases. It is up to MS Word to decide whether to show the URL as URL or plain text.

I uses Office 365, so version-wise it supposes to be always the latest. Perhaps I should have written the sub-documents as HTML+CSS and version control them.

HOWTO: sign dkms kernel module for UEFI secure boot

If you are stuck with UEFI secure boot, and desperately need to build and install a custom kernel module, then you need to know how to sign your kernel module.

To sign a dkms custom kernel, please refer my Git repository: dkms-module-util

Fix NTFS “unsupported reparse point”

Reparse point is an application-defined data that associate with a file or directory.  So it can be anything from symbolic link to mount point, and many more.

A comment in ntfs: unsupported reparse point says that plugins from Advanced NTFS-3G Features fix the problem. My own experience: works, but binary provided in is not.

HOWTO: Unwatch packages in Fedora package source (

If you don’t want to get messages from certain Fedora packages:

  1. Login  to
  2. Click Watchlist
  3. Click the package you want to unwatch, this will bring you to package Overview page
  4. There is an Unwatch  pull down which looks like the below picture. Click it and select UnwatchPackage Overview page

Note that you CANNOT unwatch the packages you maintained.

Legacy Python str.format() gotcha

In Python 2.7, str.format() works with empty string like:

python -c "print '{}'.format('')"

However, in Python < 2.6,  you will see:

ValueError: zero length field name in format

Workaround? Use %-formatting like:

python -c "print '%s' % ''"