debian

If I had been patient, it would have saved me time. One such instance is following.

From my early blogs, you might know I am using mutt to do email. Just after I get along with mutt, I started using notmuch. Because limit search in mutt is always a pain when you have multiple folders. And what better tool out there than notmuch-mutt to bind both these.

notmuch-mutt provide three macros by default.

macro index <F8> \
"<enter-command>set my_old_pipe_decode=\$pipe_decode my_old_wait_key=\$wait_key nopipe_decode nowait_key<enter>\
<shell-escape>notmuch-mutt -r --prompt search<enter>\
<change-folder-readonly>`echo ${XDG_CACHE_HOME:-$HOME/.cache}/notmuch/mutt/results`<enter>\
<enter-command>set pipe_decode=\$my_old_pipe_decode wait_key=\$my_old_wait_key<enter>" \
      "notmuch: search mail"
macro index <F9> \
"<enter-command>set my_old_pipe_decode=\$pipe_decode my_old_wait_key=\$wait_key nopipe_decode nowait_key<enter>\
<pipe-message>notmuch-mutt -r thread<enter>\
<change-folder-readonly>`echo ${XDG_CACHE_HOME:-$HOME/.cache}/notmuch/mutt/results`<enter>\
<enter-command>set pipe_decode=\$my_old_pipe_decode wait_key=\$my_old_wait_key<enter>" \
      "notmuch: reconstruct thread"
macro index <F6> \
"<enter-command>set my_old_pipe_decode=\$pipe_decode my_old_wait_key=\$wait_key nopipe_decode nowait_key<enter>\
<pipe-message>notmuch-mutt tag -- -inbox<enter>\
<enter-command>set pipe_decode=\$my_old_pipe_decode wait_key=\$my_old_wait_key<enter>" \
      "notmuch: remove message from inbox"

One for search, one for reconstructing threads and one for manipulating tags, which I missed.

Now my impatient part. I have already mapped f6 for my folder movements and in my initial days of notmuch, I only use just search. So I never cared about the f6 macro provided by notmuch-mutt. As time goes by I got very comfortable with notmuch. I was stretching my notmuch legs. I started to live more on notmuch search results date:today tag:unread than more on the mutt index. To the problem, since notmuch-mutt dump all results to a temp maildir location, can't perform flag changes back to the original maildir which was annoying, because we need to distinguish what mail you read and what not when you subscribed to most of all debian mailing list.

I was under the impression that, the notmuch-mutt is not capable of doing so and I just went like that without checking docs. I started doing all crazy hack to sync these maildirs.

I even started reading notmuch-mutt codebase.

Later, I settled on notmuch-vim. Cause I can manipulate flags sync back from notmuch to maildir.

And while searching for something, I accidentally revisited the the the notmuch-mutt macro page and saw the tag manipulation. I was like :( .

If I read about the third macro patiently when added that to config, I could've saved time by not doing ugly hacks around it.

I think I learned my lesson.

28 Apr 2026 6:33am GMT

On the 7th of September 2025, my friend Dione and I had a day trip to Vienna-the capital of Austria. We were attending a conference in Budapest, Hungary, which is 250 km from Vienna. So, it was a good opportunity to visit Vienna.

We took a morning train from Budapest to Vienna and got back to Budapest by night. However, booking these tickets turned out to be a bit complicated. There were many websites to book the train ticket-Hungarian Railways, Austrian Railways, and third-party sites such as Omio. All these websites had different prices for the same ticket.

I booked the tickets from the Hungarian Railways website as it was the cheapest. The train from Budapest to Vienna was €13, operated by Eurocity. Also, I had to pay €2 for the seat reservation on top. The train from Vienna to Budapest-operated by Railjet-was €21, along with €2 extra for reservation again-making it €23. The tickets for the two-way journey added up to €38.

The prices of these tickets were dynamic-the earlier you book, the cheaper they are. I booked these tickets more than 15 days in advance. I paid €38 for the tickets, whereas Dione paid around €100 for the tickets, as she booked at the last moment-a day before the journey.

As for the seat reservation, long-distance trains in Europe usually require paying extra for the seat reservation. This ensures that you get your preferred seat, such as a window seat or an aisle seat. Nevertheless, you will get a seat on long-distance trains because they do not sell more tickets than there are seats. Therefore, you will get a seat without reservation as well. However, we reserved our seats so that we can sit together. This helped us more in the return part of the journey-from Vienna to Budapest-which was more crowded than the train we took from Budapest to Vienna in the morning.

On another note, reservation is mandatory on some trains in Europe, but ours wasn't one of them. In addition, people also use rail passes, so an extra charge is required on top for reserving the seats for pass holders. On the other hand, local trains do not require seat reservations in general.

Our train's scheduled departure was at 08:55 from the Budapest Kelenfold station. We reached the train station 40 minutes before the train's scheduled departure. The Kelenfold station had free Wi-Fi, which was handy because I didn't have a local SIM.

A departures board at Budapest Kelenfold station.

A platform on Budapest Kelenfold station.

Our train arrived on time. I tried to find our coach number but could not find the numbers written anywhere on the side of the coach. Luckily, we were helped by a fellow passenger who directed me to look at the doors, where the numbers were mentioned clearly!

Then we got into our compartment and took our respective seats. Our tickets were checked twice - once while the train was in Hungary and the other when in Austria. Showing the PDF of the train ticket on our mobile to the ticket inspector was good enough for the purpose. Austria and Hungary are a part of the open transit Schengen area, which means this was the extent of the border control checks we had to go through.

The train also had free Wi-Fi, albeit with poor connection at times. There were no eatery options inside the train.

We deboarded at the Wien Hauptbahnhof station in Vienna. The journey was 250 km and took 2.5 hours, reaching Vienna at 11:25, which was the scheduled time.

A blue and white colored train on a railway platform

A red colored train standing at the Vienna station

At the station, we bought a 24-hour public transport pass from a ticket machine for €8. The pass includes unlimited access to all the public transport in Vienna for 24 hours. My pass was valid from the 7th of September at 11:34 to the 8th of September at 11:33. A single public transport ticket (from anywhere to anywhere) costs €2.4. A single ticket of €2.4 can be used once on any public transport in Vienna-trams, metros, and buses.

Therefore, the pass is a good deal if you are going to take at least four public transport trips in a day. Unlike the public transport pass I got in Budapest, the pass in Vienna was anonymous and not tied to the rider's name.

After getting our passes, we took the subway and went to the Schönbrunn Palace. We hopped on to the subway at the Wien Hauptbahnhof station and deboarded at the Schönbrunn subway station-the closest one to the palace. The ride was smooth; the train was pretty silent.

By the way, like Budapest, there were no AFC gates for boarding the subway in Vienna. The stations had ticket validators instead, where you are supposed to validate your tickets before getting into the subway.

These validators are in place to ensure that you use your ticket only once. Unlike AFC gates, which are present in metros of most of the countries I have been to, the ticket validators don't act as a physical barrier to enter the boarding area.

If you board the metro without validating your ticket, you will be facing hefty fines upon getting caught. I have heard that the fine is around €100. On the other hand, if you have a public transport pass like we did, then you don't need to validate it before boarding.

In addition, there were no annoying security checks either, unlike in Indian cities. In the Delhi metro, for example, you would need to scan your bags and pass through a security check before getting to the AFC gates.

Now back to the story, after alighting at the Schönbrunn subway station, we walked to the Schönbrunn Palace. One can roam around outside the palace and click pictures for free. To go inside, however, requires buying tickets. The tickets for the palace can be booked in advance on the internet. We didn't take the tickets in advance, as we decided to visit the palace at the last moment.

So we went to the ticket counter and found out that we needed to wait for 1 hour 40 minutes before going inside if we took the tickets at that moment. In addition, one ticket costs €44 (around 4000 Indian rupees). Since we had to return to Budapest in the evening and only had a few hours in the city, we decided not to go inside the palace. Instead, we clicked a few pictures outside the palace.

The Schönbrunn Palace is a UNESCO World Heritage Sit and is a historically significant place. It servedas one of the residences of the powerful Habsburg dynasty. The palace looked so good that my friend Dione said, "It seemed like the palace was built yesterday". This remark applied to other parts of Vienna we went to. For example, the subway stations also seemed like they were built yesterday.

Now, we wanted to go someplace to grab a bite. I asked my friend Urbec for suggestions on where to go. They suggested we visit the steps named Strudlhofstiege, which had the added benefit of being in a neighborhood with good bakeries and buildings.

So, we took the subway and deboarded at the Roßauer Lände station, followed by walking around a kilometer to reach the stairs.

Platform of the _Roßauer Lände_ subway station.

stairs with road in the front and trees in the background. Blue sky can also be seen in the background.

On the way, we were also looking for a place to eat. Unfortunately, it was Sunday, and Vienna closes on Sunday. That means most of the shops-including bakeries and cafés-are closed. Only places like railway stations have shops open on Sundays.

By the way, walking around in the streets of Vienna was a treat. The streets were not crowded (as it was not exactly a touristy neighborhood) and had good pedestrian infrastructure, with clean streets and separate cycling tracks. The buildings were also beautiful.

After some walking, we found a restaurant open. I grabbed the menu to check the prices. A lady at the shop asked me what I was doing, and I told her that I was browsing the menu. She said that the menu was in German. I don't know how she knew that we didn't know German, but it seemed like a racist thing to be told.

We roamed around further and found a café by the name of Blue Orange, where we ordered coffee and croissants. When we got our order, the waiter told us that they were having some issues, so they wouldn't charge us for the croissant if it wasn't good.

My friend and I took a bite, and both of us didn't like the croissant. After some time, the waiter came to us and asked whether the croissant was okay, to which we said no. Therefore, they didn't charge us for the croissant. This was the first time something like this happened to me. It felt like I was in a different world. I added a small tip at the end for this gesture, which I had to put in a jar at the counter.

The cappuccino I ordered was €4.50, while the espresso that Dione ordered was €3.60. The croissant would have been €3.60. I remember Paris having cheaper croissants!

Then when the waiter brought our drinks out, they automatically gave me the espresso and Dione the cappuccino. Dione found this funny because there is a stereotype in her country (Australia) that men drink strong black coffee, and women drink milky drinks like cappuccinos. She found it interesting that this stereotype seems to exist in Austrian culture too.

We hopped on a tram to reach the nearest subway station and went to the Wien Hauptbahnhof station to have something before we caught our return train to Budapest.

Trams with buildings and the blue sky in the background

At the station, I had Esterhazyschnitten and Punschkrapfen (thanks, Urbec, for the suggestion). The lady at the shop warned me that punschkrapfen had alcohol in it, to which I said okay.

Esterhazyschnitten was a cake made of almonds, while punschkrapfen was a jam-filled sponge cake, soaked in rum. Esterhazyschnitten was my favorite out of the two. The punschkrapfen was too sweet for my taste.

While the station was well-built, there were a couple of things about the Wien Hauptbahnhof station that we didn't like. There were no seats inside the station, so we had to eat outside the building. Also, the toilets needed to be paid for. It costs 50 cents to use the toilets at this station.

The Vienna train station had departure boards all over the place. So, we went to the platform our train was to arrive on.

A departure board in Vienna displaying information about the trains

Platform and tracks at Wien Hauptbahnhof station.

When our train arrived, we had some difficulty locating our compartment. This train was operated by a different company (Railjet) than the one we took in the morning (Eurocity) from Budapest to Vienna, and we were able to locate the coach numbers using the digital board at the station. Each compartment had a digital board next to it on the station displaying the coach number. However, that wasn't the problem. Even after reading the coach numbers and trying to find ours, it didn't appear where we expected in the sequence.

When we were not able to find our coach for a while, we asked a ticket inspector of the train who was standing on the platform. He directed us towards the front side of the train. So we started running to the front side as we didn't know how long the train stops.

As we ran toward our coach, we found out that the engine of the back train was connected with the last compartment of the train at the front. At that point, we realized that the train was a combination of two trains. At a later station, the train on the back side parted ways and went towards Vienna Airport.

A red colored train standing on the platform of Budapest Kelenfold station.

We had a smooth journey and reached Budapest a couple of hours later.

Vienna is a beautiful city; we enjoyed being there, and we would like to visit the city again!

That's it for now. Signing off. See you in the next one!

Credits: Thanks to Dione and Badri for proofreading.

28 Apr 2026 2:29am GMT

Yesterday, I had to add support for running KVM virtual machines inside an LXC container. More as a reminder to myself, in case I ever have to do this again, here the simple recipe:

LXC Container Config Adjustment

Enable lxc.autodev and execute hook script to be executed after initial /dev creation (updated 20260428: lxc.cgroup2.* instead of lxc.cgroup.*):

[...]

# Auto-create /dev nodes and add native KVM support to the LXC container
lxc.autodev = 1
lxc.hook.autodev = /var/lib/lxc/.hooks/lxc-hook.kvm-support
lxc.cgroup2.devices.allow = c 10:232 rwm
lxc.cgroup2.devices.allow = c 10:238 rwm
lxc.cgroup2.devices.allow = c 10:241 rwm

[...]

[added 20260408] On the internet, you can find a recipe that simply bind-mounts /dev/kvm from the host in to the LXC container. However, this fails if group ID of POSIX group kvm differs between host and container.

LXC Hook Script for KVM Support Enablement

The following script I placed at /var/lib/lxc/.hooks/lxc-hook.kvm-support (on the LXC host!):

#!/bin/sh

# set up native KVM support in LXC container
mknod -m 0660 ${LXC_ROOTFS_MOUNT}/dev/kvm c 10 232
chown :kvm ${LXC_ROOTFS_MOUNT}/dev/kvm
mknod -m 0660 ${LXC_ROOTFS_MOUNT}/dev/vhost-net c 10 238
chown :kvm ${LXC_ROOTFS_MOUNT}/dev/vhost-net
mknod -m 0660 ${LXC_ROOTFS_MOUNT}/dev/vhost-vsock c 10 241
chown :kvm ${LXC_ROOTFS_MOUNT}/dev/vhost-vsock

27 Apr 2026 9:44am GMT

fidzu : debian

28 Apr 2026

Planet Debian

Abhijith PA: Patience could've saved me time.

Ravi Dwivedi: A day in Vienna

27 Apr 2026

Planet Debian

Mike Gabriel: KVM Support inside LXC Containers [updated]

LXC Container Config Adjustment

LXC Hook Script for KVM Support Enablement