Ask Ubuntu General Room

IanC

12:00 AM

@NathanOsman you did mathematics on college? :O

@edwinksl I'll try to invite him to chat

but I'm going have to rely on analogies

edwinksl

i would just suggest OP to read a book to understand the basics

it is clear he's not ready to understand what you wrote

IanC

I'm looking for one of those "spheres colliding" reaction gifs, maybe it gives him an idea

Nathan Osman

@IanC Nope.

But I did develop a personal interest in mathematics.

Twiddles thumbs...

edwinksl

lol

how long should that take

Ubuntu Questions on U&L

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Q: Create LXD containers on machine with no internet connection

Server: Ubuntu 16.04 Server, x64, no internet connection I have LXD installed but am having trouble getting an image to that server to use as a baseline for containers. I have tried two options so far, with failed results. 1) Export image (Xenial)(meta.tar and rootfs.tar) from machine with ...

edwinksl

12:06 AM

@IanC the real answer requires the use of pKa's :)

Nathan Osman

@edwinksl It's Apple, so at least we can expect some level of competence.

Probably hear back within a day or two.

IanC

@edwinksl, yeah, chemical equilibrium math can get nasty on those complicated "shared" ion cases

I did find this video, which I think I'll link the OP youtube.com/watch?v=dUMmoPdwBy4

(what does OP stand for btw?)

edwinksl

original poster

whoever asked the question

Nathan Osman

Welp.

edwinksl

?

Nathan Osman

12:08 AM

I don't think that's a good thing.

edwinksl

obviously he was going to get it :P

Nathan Osman

Yes, but now the finality is sinking in...

edwinksl

there is no secret we don't learn until s*** happens

perhaps this is something this country simply needs to go through

Nathan Osman

I... I guess I would have to agree.

IanC

@edwinksl the OP could at least accept or upvote my answer after all my effort :'(

Nathan Osman

12:11 AM

Some folks gotta learn the hard way.

edwinksl

yeah this country hasn't seen anyone quite like trump yet

plenty of other european countries have though

@IanC i am not sure why the other answer has a downvote

IanC

it's sad how hate has been a effective crowd controller in the past, how it's easier to make lots of people hate something/someone than embrace something :/

Serg

I'm about to go mad , wall command pisses me off so freakin much

edwinksl

@Serg patch it? :)

Serg

@edwinksl my skills are not good enough to patch it

IanC

12:16 AM

@edwinksl, the other answer is right, it says mostly the same. Probably downvoted because it was hard for the OP to understand? not sure too

edwinksl

@Serg git gud xD

@IanC yeah that's probably it...

Serg

Some how I suspect it has something to do with systemd , and oh boy . . .

edwinksl

when in doubt, blame systemd :)

Serg

WTF Python pics.onsizzle.com/…

edwinksl

that's the classic misuse of is though

and that python caches -5 to 256 or something like that

Serg

12:22 AM

still fails with ==

2*1000000 == 2*100000
False

edwinksl

number of zeros is different though

6 on left, 5 on right

Serg

hmm , missed one

Quill

is is for object reference, not value equality

IanC

you guys have a good notion of TCP/IP protocols?

Serg

Yup , know that

Still funny

And

2*10 is 2*10
True

Why is the objects the same in this specific case anyway ?

>>> 2*10 is 2*10
True
>>> 2*100 is 2*100
True
>>> 2*1000 is 2*1000
False
>>>

Does it cross some kind of limit ?

edwinksl

12:26 AM

@Serg stackoverflow.com/questions/15171695/…

Nathan Osman

is compares objects.

So the interpreter reuses small numbers.

edwinksl

>>> a = 256
>>> b = 256
>>> a is b
True
>>> a = 257
>>> b = 257
>>> a is b
False

Nathan Osman

From the docs:

> "The current implementation keeps an array of integer objects for all integers between -5 and 256, when you create an int in that range you actually just get back a reference to the existing object. So it should be possible to change the value of 1. I suspect the behaviour of Python in this case is undefined. :-)"

docs.python.org/2/c-api/int.html

Granted, that's for Python 2.x but I doubt that changed in Python 3.

edwinksl

still the same, i did my example in python 3

Nathan Osman

So there's your explanation, @Serg.

edwinksl

12:28 AM

dat :-) doe

Serg

When typing in the Python shell each line is a completely different statement, parsed in a different moment, thus:

>>> a = 257
>>> b = 257
>>> a is b
False

But if you put the same code into a file:

$ echo 'a = 257
> b = 257
> print a is b' > testing.py
$ python testing.py
True

/facepalm . . .

so objects also depend on time of compilation ?

Nathan Osman

Or you could just do:

a = 257 ; b = 257 ; a is b

Same result.

Serg

Sigh . . . . even python has its problems

edwinksl

the problem here is the misuse of is

Nathan Osman

@Serg It's not a problem when used correctly.

Quill

12:34 AM

lol what do you expect when you try to use an object reference operator for value equality

Serg

well, everything in python apparently was supposed to be an object , but nobody mentioned that there's a catch to it as well

edwinksl

not sure if i follow

Serg

* at least nobody mentioned it to me while i was starting to learn it

edwinksl

is and == do totally different things, if you use them for unintended uses, then you can't reasonably expect things to work as you expect

Nathan Osman

^--- this

@Serg Everything is an object. But what you were trying to do isn't what you were doing (comparing objects instead of values).

a = 256 is basically saying "the variable 'a' is a name that will refer to an object with a value of 256".

So comparing against a with the is operator is saying "compare [object] to the [object] that a refers to".

The == operator, on the other hand, compares the objects' values.

Serg

12:41 AM

I know it's comparing objects. I know what "is" does. But wouldn't 257 is 257 temporarily create an object ? of the same value ? Instead we're greeted with a limit

Nathan Osman

It's not a limit. You're using it for the wrong purpose.

Whenever you write a program, you are implicitly entering into a contract. You (the programmer) are agreeing to use the language as the documentation describes and the compiler (or interpreter or whatever) is agreeing to operate according to the documentation. Only then can a programmer expect an application to work as intended.

Without this agreement, programming would not exist.

Serg

that's is true

CodeX

@lanC what about it

IanC

@CodeX nothing specific so far, just been reading a book and was wondering what approach you suggest to study it?

@CodeX Should I read each protocol RFC?

CodeX

12:59 AM

what is your goal @lanC

IanC

@CodeX I always been curious about some network security issues, I just want to be able to understand things better

CodeX

@lanC you can start from basic .. IP subnetting .. OSI model ..then how tcp and udp connection works ..

IanC

I'm reading a book I found online, so far so good, but last time I tried to read a TCP/IP book I was understanding good until page 200-300 where things started getting a little too complicated haha

CodeX

haha

it becomes more boring if you read about routing and other stuff

IanC

btw, I have a small doubt

Serg

1:07 AM

CodeX

what is it

Serg

@CodeX you can't see the image ?

CodeX

Wikileaks : 294,548 emails from Turkey's ruling political party, Erdoğan's AKP

oh sorry I was asking LanC @Serg

IanC

@CodeX the book says that packages that goes out in the internet (as opposed to internal networks) need to have an IP approved by InterNIC (for obvious reasons). What happens if a manipulated package with a spoofed IP runs out the internet? Does the internet provider readily sees the anomaly and adress the issue to the source computer?

CodeX

between I was really not able to see the image and post the message for sometime .. because of this DNS thing

IanC

1:11 AM

I just imagine if it was the case, hackers would be easily tracked

the internet provider would just look for some spoofed packages and check which subnet it's coming from

CodeX

@lanC I dont know the technicality of it .. but from what I know .. it is possible to spoof IP .. and it can be stopped at ISP level .. since I work for ISP I have seen issues with spoofed IP from other countries

Packages = Packets I believe ?

ƎpᴉʇʎXD

i'm sick of pokemon go..

Serg

Having a unity laucher item that can dim screen brightness, with just one click - man that was a good idea

Maybe I should post it as Q&A ?

CodeX

me too .. I have that launcher .. full bright and very dim xD

ƎpᴉʇʎXD

@Serg go for it

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