Ask Ubuntu General Room

you build the environment (3d editor) define characteristics physics etc then you bbake it (calculate the physics state per frame) and then you render it to a movie or simgle frame pictures

TheWanderer

hmm

Nathan Osman

Yup, that's an accurate summary.

Videonauth

1:14 AM

those headphones as picture i posted earlier where amde in blender too

god i cant type today

Videonauth

1:33 AM

Oh my ... ~1500 views already? askubuntu.com/q/977138/522934

sad i cant see the anonymous votes

Ubuntu Questions on U&L

1

Q: removed lib modules folder after every reboot

uname -r: 4.13.0-16-generic (ubuntu 17.10 server) I have a problem that iptables doesn't work after a reboot: iptables-apply /etc/network/iptables [ ok ] Stopping fail2ban (via systemctl): fail2ban.service. Applying new iptables rules from '/etc/network/iptables'... modprobe: FATAL: Module ip_t...

Nathan Osman

I'm having fun with a race condition:

0

Q: Correct way to queue items for a worker goroutine?

I am writing an app that allows users to upload files and queue them for processing. My approach to this is to create a goroutine for processing uploaded files and to use a channel to signal that a new file is ready for processing. Basically, the processing goroutine does this: for { while ...

go race-condition channel

:|

Videonauth

1:49 AM

why not simply put a variable as lock, so the next item only gets processed when the first one is done?

TheWanderer

does Go have interfaces?

Nathan Osman

Locking is slower than using channels in Go.

@TheWanderer Yes.

TheWanderer

can you use that?

Nathan Osman

Woot! I got a clever answer already.

@TheWanderer What do you mean by interfaces? I should have asked that first.

TheWanderer

like Java interfaces: callbacks

Nathan Osman

1:57 AM

Ah.

Not like Java, no.

In Go, an interface defines a set of methods that a type must implement.

TheWanderer

so an abstract class

maybe you should just use Java :p

wait no

PHP! :D

Nathan Osman

No.

No. No. No.

Besides, I have the answer now.

TheWanderer

P

H

P

Nathan Osman

Just gotta give the channel a capacity of 1.

TheWanderer

no idea what that even means

Nathan Osman

2:02 AM

Channels are used to communicate between goroutines.

(Which are like mini threads.)

So one goroutine sends on the channel and the other receives.

The only catch is that both operations block by default.

You really ought to learn Go :D

Videonauth

new flavor? :P

Nathan Osman

O_o

Videonauth

2:22 AM

hahahaha --> unix.stackexchange.com/q/405151/166226

Videonauth

2:52 AM

@NathanOsman btw. on this script the luaunchpad logo does not sow up in edit field the others work fine

Eliah Kagan

@Terrance Should it be undeleted? That can be done. I could cast an undelete vote, and since it has two of them, that should be sufficient. Would you then answer it, and in your answer would you be able to explain why enabling that repo would address that problem specifically?

Videonauth

@EliahKagan That was at least my assumption and thus gave my undelete vote (the second one)

Terrance

3:20 AM

@EliahKagan I believe so. After looking at the files that are saying that they will not be installed they seem to be coming from kubuntu-ppa/backports when I look at them in my apt-cache policy command.

Terrance

3:35 AM

Honestly, it really is not a big deal if it gets undeleted. OP may not want to install the kubuntu-desktop anymore.

Eliah Kagan

5:41 AM

@Terrance Sorry, I was afk. If you still want to post an answer, and your answer would use the specific details of the question while also benefiting people besides the OP, then I think it's reasonable to undelete it. I'd definitely cast my undelete vote if that is the case. So you can let me know.

Eliah Kagan

6:22 AM

To clarify: if you think the question facilitates an answer that'll help others, I'll absolutely vote to undelete. If the OP doesn't want their name on it, they can have SE dissociate it from their account (then it'll show as being by a grayed out "anon" user). I'm not generally reluctant to undelete other users' posts. But if it's only to help them, not others, then I'm inclined to go by their choice to delete it. That isn't site policy or anything. But for me that's the deciding factor here.

Zanna

10:52 AM

Thanks for that edit @terdon :) Much appreciated

terdon

11:04 AM

@Zanna You're very welcome, it was the right answer.

Eliah Kagan

@Zanna I just noticed that in that answer you mention:

> You can remove the quotes, unless your username has special characters, or you can...

But why would it be a problem for the username to contain characters of the sort that sometimes trigger expansions by the shell? Are more expansions applied to text expanded from ~?

My quick testing suggests this does not happen, but are there versions (in Ubuntu) where it occurs as a bug or something?

I have found this. But all versions of (including EoL releases) have had Bash 4, right?

Zanna

I was just worrying about this... it would be bad if it did get expanded further

I shall remove those words...

Eliah Kagan

Oh, actually some old releases have had older Bash versions.

old-releases.ubuntu.com/ubuntu/pool/main/b/bash

No currently supported release does, though. My 14.04 system has bash 4.3.11. Nobody should (even be able to?) have stuff in their username that would trigger problems. But people could have weird home directories. I'd suggest either removing the warning as it effectively doesn't apply to Ubuntu, or clarifying that it's the home directory, not just the username, to which the weirdness caveat applies (as if the current warning is needed, it doesn't do the full job of warning about the problem).

Ubuntu Questions on U&L

11:23 AM

-2

Q: How do persistence Kali Linux in different devices?

Consider two drives say cdrom, USB. In cdrom burned Kali Linux. How do persistence to USB related to cdrom?

linux ubuntu kali-linux

Zanna

@EliahKagan thanks a lot for clarifying :)

Eliah Kagan

12:07 PM

@Zanna No problem! How do you feel about my subsequent edit? Feel free to roll it back or re-edit if you don't like it!

Zanna

Awesome edit! Thank you!

Eliah Kagan

You're welcome.

Android Dev

1:36 PM

Hey @NathanOsman your OP3 can be rooted with one ADB command

Just FYI :D

And yes that's without unlocking the bootloader

Ubuntu Questions on U&L

2:08 PM

0

Q: What would go wrong if i move /var from one machine to another?

I have a AWS EC2 instance (lets call it Eye1) with a 500GB EBS as secondary storage mounted at /var. Now I want to migrate my environment to a different EC2 instance (lets call in Eye2). The new instance was initialised by other team members by installing python2.7, tensorflow, opencv and other ...

ubuntu amazon-ec2 aws

Ubuntu Questions on U&L

2:54 PM

0

Q: mdbtools fatal error: sql.h when installing

I want install mdbtools from source and I get the following error fatal error: sql.h: No such file or directory so I read the following solutions, but I don't really understand them https://forums.freebsd.org/threads/46299/ https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=189382 I did the ...

linux ubuntu make

dessert

3:05 PM

Do we have a policy about people who just want their assignments done? Those two users seemingly exist for that purpose only and funnily enough are attending the very same course, see their questions:
https://askubuntu.com/users/758109/panos-mikael
https://askubuntu.com/users/760366/akis-tachmatzidis

Videonauth

@dessert if one shows effort to produce a script ans asks where it fails, hes fine if the other simply asks his assignment question but doesnt show effort he gets DV

terdon

3:18 PM

@dessert There's a huge difference between them. One just posts the homework assignment expecting us to do it fot them, while the other tries, shows what they have and only asks for help on a specific aspect they're having trouble with.

The first is off topic as simply "too broad". The second is fine and worth upvoting.

dessert

@terdon That's right, unfortunately the bad guy does it some days earlier every time. :(

terdon

@dessert So? Just downvote and vote to close.

I just closed the one you answered as a dupe of the one the other guy asked. That was a far better question (and age is irrelevant when choosing which duplicate to use as the master).

dessert

@terdon Oh, that's a good solution, thanks!

terdon

It cost you the +15 of the accept, I'm afraid. Sorry about that!

dessert

@terdon You expect me to ignore very interesting problems, but I'll try. But then again, I'll solve it for myself, just wait for the other guy and compare mine with his solution. :)

Videonauth

3:25 PM

they seem to have the same course with the same professor and homework assignments

dessert

@terdon No worries, but actually this -15 didn't show up until now – are they even taken from me?

Videonauth

one of them doesnt do it, and simply asks directly here for solutions, and the second one takes a while and treis to solve it but then maybe struggles and comes here with his question

dessert

Exactly! Let's look out for the lazy one…

terdon

@dessert Hmm. Maybe not. I think so though. It might take a few minutes because of caching. Brace yourself for the loss!

Pandya

Will gcc command/process (in gnome-terminal) continue running if I close the lid of laptop and screen-locks?

dessert

3:28 PM

@terdon You're right, there it is – evil mod!

;)

I think so, but why don't you just try it with e.g.
for i in {1..20}; do echo $i; sleep 1; done

Videonauth

@Pandya if your laptop doesn't suspend when the lid is closed it should still run

Pandya

@Videonauth yes, it doesn't suspend, it (clausing the lid) just cause for screen-off and lock

Videonauth

then it should stil run if you open it and unlock your screen, but if that compilation is important, try it with a shell script first, if that is still running you can be sure your gcc will be doing what he does still when you close the lid

terdon

If it doesn't suspend, then everything should continue to run, yes.

Pandya

@dessert oh! it looks stopped or slows down atleast! :(

dessert

3:33 PM

@Pandya Really? That's unexpected. oO I do that all the time and it works flawlessly.

Do you say closing the laptop lid slows down sleep? That's actually quite funny!

Pandya

@dessert Yes, I've just tried: typed the command, press enter and suddenly closed the lid for about 40 seconds and when I opened the lid and unlocked the screen, it reached to 10 only!

@dessert I think locking the screen may allow process to continue but I need to check what happens when I close the lid.

How do I check it?

dessert

@Pandya I have no clue.

terdon

@Pandya Why are you so sure it doesn't suspend? Also, try printing to a file and not the terminal: for i in {1..20}; do echo $i; sleep 1; done > file

Pandya

@terdon Yes, well I want to check it, is there any gsettings scheme I can check with, let me search...

>$ gsettings list-recursively | grep lid
org.gnome.settings-daemon.plugins.xrandr default-monitors-setup 'follow-lid'
org.gnome.settings-daemon.plugins.power lid-close-suspend-with-external-monitor false
org.gnome.settings-daemon.plugins.power lid-close-ac-action 'suspend'
org.gnome.settings-daemon.plugins.power lid-close-battery-action 'suspend'
org.gnome.settings-daemon.plugins.xrandr default-monitors-setup 'follow-lid'
org.gnome.rhythmbox show-song-position-slider true
org.gnome.shell disable-extension-version-validation false

terdon

> org.gnome.settings-daemon.plugins.power lid-close-ac-action 'suspend'

Pandya

3:39 PM

Hmm...

terdon

That would suggest it's suspending. But just put your ear next to the machine and listen to it. You should be able to hear the fans stop, disks stop spinning etc

2

Pandya

Btw, if suppose I don't close the lid and screen automatically off and lock (with lid opened) then Can we surely say that process would be running? @terdon @dessert

terdon

If it's just the screen, then yes. Just like in a normal desktop: if you unplug your screen, nothing is affected.

dessert

@Pandya Not at all! You could run low on battery power, there could be a blackout, your hard drive could suddenly fail, your CPU could suffer a terrible meltdown, or your evil kitty could press Ctrl+C. There is no way to be absolutely sure your process will continue to run.

Pandya

Let me pop-out my actual problem: I need to run a c programme for about 14 hours (for 200000 iterations). Now here I want two things. 1. Process shouldn't stop in any case (I'll going to put my lapttop plugged in) 2. It would not be a good idea to stay the screen on always since it may reduce the life of screen/battry. So, I hope that screen may off and lock but process should continue anyway. I am ready not to close the lid. @terdon @dessert

terdon

3:45 PM

@Pandya Then just don't close the lid.

I would also run it in the background so you don't stop it by accident. But I've run processes that take weeks with absolutely no problem.

Charles Green

Evil kitty will come and sit on the keyboard

terdon

Which is why you run it in the background :)

Sergiy Kolodyazhnyy

Or run command in screen session and log out from whatever tty you're using

dessert

@Pandya see man xrandr how to turn off the screen and do only that

Pandya

@terdon ok. Thanks a lot for your suggestion "just don't close the lid" :)

dessert

3:48 PM

32

Q: Turn off monitor using command line

I am runnning Ubuntu Server on my laptop. There is really no reason for the screen to be on. I have been trying to use this command to turn the screen off: sleep 1 && xset dpms force off The problem is I get the following error unable to open display "". Any idea what is going on / what is ...

server display monitor x11

Pandya

Btw, I'm not running a server.

cl-netbox

Hello everybody :)

dessert

@Pandya Me neither, there's no difference when it comes to that.

Pandya

ok

dessert

@cl-netbox Good evening!

Charles Green

3:51 PM

@cl-netbox Hello!

cl-netbox

@dessert Good evening to you too ! :)

@CharlesGreen Hello Charles ! :)

I thought you wanted to quit @SergiyKolodyazhnyy ? :D :D :D Good morning Sergiy ! :) How are you doing my friend ?

Pandya

Btw, I just found the another idea to make sure laptop/process running: take your ear toward FAN!

dessert

@cl-netbox A fellow de_DE.UTF-8, how nice! ;)

cl-netbox

@Pandya hardware solution beats software solution ... nice ! :D

2

@dessert yup, how do know that I'm from Germany ? :)

Videonauth

@cl-netbox remembers the isolation tape over webcam lense answer

dessert

3:58 PM

@cl-netbox askubuntu.com/users/260935/cl-netbox I just assumed you didn't lie about that.

terdon

19 mins ago, by terdon

That would suggest it's suspending. But just put your ear next to the machine and listen to it. You should be able to hear the fans stop, disks stop spinning etc

2

Charles Green

@Videonauth I thought it was a sticky-note

cl-netbox

@Videonauth you are speaking in riddles (again) hahaha ... good afternoon to you ! :)

Videonauth

sec let me find it

cl-netbox

Hi terdon ! :)

terdon

3:59 PM

hi

dessert

20

A: How can I disable my webcam?

How about just taping it with some black colored tape? Take some black tape and put it on the webcam. Webcam disabled successfully! Unlike the answers above, this method works against malware attacks that try to enable your webcam as well!

@Videonauth found it (or at least one of those answers!)

cl-netbox

@dessert no, I didn't ! :)

Sergiy Kolodyazhnyy

@cl-netbox I am still in the process of quitting ;)

terdon

86

A: How to block input to webcam?

A foolproof way to block webcam input Picture provided by Darkreading.com

cl-netbox

@SergiyKolodyazhnyy process ... hahaha :D

Charles Green

4:01 PM

My computer has a booboo?

3

cl-netbox

@CharlesGreen ask @ParanoidPanda ! :D

Pandya

@terdon oh! I missed that message. You're always perfect! LoL Thanks.

terdon

Always perfect huh? You really should meet my girl friend :P

Sergiy Kolodyazhnyy

@terdon is she as good with Perl as you are ?

terdon

Heh, no. She's an artist, not a geek at all.

Sergiy Kolodyazhnyy

4:07 PM

awesome

dessert

4:25 PM

2

Q: How to copy random files to a specific folder?

I have vast collection of files (6.5 million) in several folders and sub-folders and i want to copy some random picks (about 200k-300k files) to a directory to make a randomized sample. the folder tree is this (just a small sample) inside each folder there are several files . ├── articles.0-9A...

command-line copy

This really got me thinking: How many files does a Ubuntu system have on average?
$ sudo find / -type f | wc -l
956884
So I'm nearly a millionaire – How many files do you have in your possession (without external devices)?

Sergiy Kolodyazhnyy

$ sudo find / -printf "%i\n" | wc -l
[sudo] password for xieerqi:
find: ‘/run/user/1000/gvfs’: Permission denied
1225872

That doesn't take into account all the temporary files being created and cache and stuff

Better idea probably would be

$ find $HOME -type f -not -path "*.cache/*" -printf "%i\n" | wc -l
39860'

dessert

5:01 PM

$ sudo find / -printf "%i\n" | wc -l
1212331
$ find $HOME -type f -not -path "*.cache/*" -printf "%i\n" | wc -l
405980

cl-netbox

$ find $HOME -type f -not -path "*.cache/*" -printf "%i\n" | wc -l
1066

Pandya

And another thing: is it ok to plug (charging) in a laoptop for whole the night? (currently 80% battery, so it is going to full soon and laoptop is going to plugged in until the morning)

cl-netbox

@Pandya why not ? it's okay to do it. :)

Pandya

Right. It will automatically stop consuming current after battery is full. ok

cl-netbox

@Pandya yes :)

dessert

5:07 PM

@Pandya I always take out the battery when the laptop is plugged in and just charge it in standby, heat is poison to lithium-ion batteries. That's nearly a question of faith though.

cl-netbox

@dessert there are so many different opinions on that topic ... I used to do it too some time ago - but it made no difference ... battery doesn't live longer or shorter. :)

TheWanderer

@dessert heat actually makes lithium batteries charge faster

grooveplex

5:30 PM

The First Post Review queue was marked with a red dot.. what does that mean?

dessert

@TheWanderer Some even store their battery in the fridge, but I don't think they also charge it there. Unless!

@grooveplex That's supposed to mean that there's lots of work waiting in that queue. There are however rumors the system doesn't work that well…

grooveplex

ok, I see. Thanks @dessert.

dessert

5:52 PM

@grooveplex You're welcome.

Ubuntu Questions on U&L

6:05 PM

0

Q: Window frames in Ubuntu KDE do not show up

I recently removed XFCE and installed KDE on my HP chromebook. Everything in KDE functions fairly well to my knowledge except for one. The applications themselves run fine, but the window frames are not present. I cannot move the windows nor can I close them, minimize them, and they all stay glue...

linux ubuntu kde window

Nathan Osman

7:34 PM

I'm going to give VS Code a try.

Seth

You haven't tried it yet?

It's quite nice

Nathan Osman

I have but not in any day-to-day workload capacity.

In other words, actually using it for a project.

Sergiy Kolodyazhnyy

8:02 PM

@terdon btw, question about the question you merged today (askubuntu.com/q/977410/295286) Answers there are from one question, comments under question are from the other. Would that make sense to nuke the comments then and just make the question and answer one and whole ?

Seth

Just purge them all Sergiy?

dessert

@Seth that! Already did that with mine…

Seth

ok, done.

Sergiy Kolodyazhnyy

Perfect-o ! thanks !

dessert

@Seth Do you mind removing this one too? askubuntu.com/questions/977410/…

Seth

8:13 PM

sure

Fabby

8:33 PM

Videonauth

@Fabby Nuke it from Orbit?

Fabby

Animated GIF beats nukeitformorbit.com

@terdon low-tech solution to high-tech problem: That's how I like my solutions!

Byte Commander

@Fabby well, that escalated quickly

Hi :)

Fabby

(grinning)

I've had a terrible week.

Byte Commander

Me too, and next week isn't gonna be better. I'll have exam week then.

Fabby

8:38 PM

Customer asks us to do a bubble DR test, keeps me up all night, asks me to break down the bubble 2 minutes after I go to sleep, I wake up, have it torn down and next day asks:

Can we test in 2 weeks again???

@ByteCommander OK, you win!

/shrug...

@JourneymanGeek That only happens in movies!

(or at least: doesn't happen to my fridge...)

yours @ThomasWard ???

It's very lively here for a Friday-night!!!

Normally I only hear crickets...

Byte Commander

What's a bubble DR test?

Thomas Ward

@Fabby hm?

Fabby

Do your know what a DR Test is?

Byte Commander

nope

Thomas Ward

ah, yep.

Byte Commander

8:43 PM

at least not by the name

Fabby

@ThomasWard You don't strike me as the guy with an empty fridge...

Thomas Ward

Disaster Recovery test/drill

@Fabby after last night's boozefest I had, it's mostly empty right now :P

Fabby

:D :D :D

Thomas Ward

DR test: Disaster Recovery Test, IT Evil 101.

Shut off the production, test your offiste DR infrastructure to test failover in the event of a major destruction

Byte Commander

Only results on DDG for "bubble dr test" were medical stuff... :D

Thomas Ward

8:44 PM

also

test backups.

also

pray.

Fabby

No praying with my tests...

Thomas Ward

@Fabby no i meant...

Fabby

They can go overtime, but no praying is involved...

Thomas Ward

pray when you turn everything back on

because your SAN could be fubar if it didn't gracefully power off and the RAID is screwed

Fabby

Like I said: not with mine...

Thomas Ward

8:45 PM

:P

Fabby

Anyway, when I was a kid, DR Testing meant:

Call the DR Test site, call the movers; call the storage site, call the off-site backup provider, have them all deliver everyting at the same time in a working condition

Videonauth

schroedingers backup? the state of the backup is unknown unless attempted playing it back?

4

Fabby

@Videonauth Starred!

mount all the equipment, restore the back-ups, test all servers, break everything down again, move it all back to storage.

nowadays it's an 8-hour exercise.

@ByteCommanderthere are 3 basic DR tests:

1. comms fail-over test (needs customer NetEng and our NetEng)

Videonauth

:)

Fabby

2. DC fail-over: Shut down primary site, fail-over to secondary.

3. Bubble test.

now a bubble is a snapshot of the DR environment in the second DC completely firewalled off and brought up while production site keeps running.

That's all it is... Not rocket science.

Byte Commander

8:51 PM

aha, so the intention is not to accidentally break down prod while testing with that last one :D

Fabby

Just a combination of storage, compute and network technology.

Yup: don't touch PRD

Byte Commander

sounds fun

;-P

Fabby

It is... But it's not if it's the first one, takes 2 weeks of scope definition, 4 weeks of execution and the customer wants it done all over again in 2 weeks time when none of the lessons learned have been implemented because their beancounters went for a drink and abandoned the test and I was awake for 30 hours to give them what they wanted...

"Hey, you're German, why don't you get the Germans to set everything up next week while we celebrate Thanksgiving?"

Forgetting that: There's like 2 of us in Germany (Sales organisation doesn't count: they're 30 or so)

and maybe 8 techs in the UK.

And I'm the only one working in both EMEA and AMER...

Videonauth

omg lol

Fabby

And on top of that, these are West-coast guys so they wake up when my day is finished...

I'm just pissed off is all.

And the Sales guys will probably kow-tow and give the re-test away for free.

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