If I'm unhappy about something a binary does, let's say /sbin/ip, how do I find the source code and where to send a patch to?
I would like to know where to find the source code of Ubuntu. I'd like to see how far it is "open source".
Why can't I define a default constructor for a struct in .NET? Windows 10 64-bit requirements: Does my CPU support CMPXCHG16b, PrefetchW and LAHF/SAHF? I'm currently trying to find out whether or not it would be a good idea to update my slightly dated notebook (Windows 7, 64-bit) to Windows 10. The problem is that Microsoft states in their  that to use the 64-bit version of Windows 10, a processor which supports CMPXCHG16b, PrefetchW and LAHF/SAHF is needed. I know that my processor is 64-bit (Intel Core i5-2430M @ 2.40 GHz) but I don't know how to find out whether it supports CMPXCHG16b, PrefetchW and LAHF/SAHF, and I have no idea what these mean.  I tried using Google and got no results that made sense to me, only some comparison of my i5 and a similar AMD processor. I also checked Intel's ARK website. If somebody could point me to where I can get more info I would be really grateful. What are the ways to solve cubic equations? Cubic equations of the form $ax^3+bx^2+cx+d$ can be solved in various ways. Some are easy to easy to factor in a pair, for some the roots can be found out by trial-and-error, some are one-of-a-kind, some can be reduced to a quadratic equation. A compilation of all possible ways to solve cubic equations would be very helpful for students and learners. For a physics major, what are the best books/references on Greens functions for self-studying?  My mathematical background is on the level of Mathematical Methods in the physical sciences by Mary Boas. Couldn't find hvm kernel for Ubuntu tree This command:  virt-install   \    --name bla  \    --ram=1024  \    --disk path=/home/me/libvirt/images/bla.qcow2,bus=virtio,size=10  \    --location /home/me/Downloads/ubuntu-18.10-desktop-amd64.iso   Reports:  ERROR    Couldn't find hvm kernel for Ubuntu tree.   How can I fix this?  (Since there are many duplicate posts and answers with regard to this issue, I am answering it, too.) "debconf: DbDriver "config": config.dat is locked by another process: Resource temporarily unavailable" while installing packages How to prove the continuity of the metric function? What could be the reason covid19 death data shows strong periodic trends? The covid19 death data for US shows strong periodic trends. It does not make sense to me that people die periodically.   What could be the reason to having such data? I thought it might be the reporting artifacts, for example, people always update data at Monday, but the period seems to be 3-4 days. There are several things that I don't understand. I know that zero is a real number, but I'm confused on the how and why aspects. What defines a real number, compared to a number that's considered non-real? For what reason is zero real, and how is it that a value such as infinity isn't when zero is?  Also, what purpose does zero even have? It's obvious that it's used as a place holder, but what value does it have alone? What makes it any different from other numbers? I realize that it is typically interchanged with nothing, but that would technically mean that zero is nothing—and that's not true. People have told me already so many times that zero does not necessarily mean nothing, and I figured it out a long while ago anyway. So, what I want to know is the actual value that can be associated with zero.  However, my question brings up another topic that has been argued and disputed about and disagreed on for years. Zero divided by zero, or 0/0. There are a lot of varying answers about this, but what's been constant throughout everything is that people claim 0/0 is not a real number. So, if I may ask, why is it that zero is considered a real number, and not 0/0? And why is it considered non-real in the first place? True, there is no defined value, but the expression is anything but meaningless; if it was, then there wouldn't be so many people trying to understand it. I guess what I'm trying to figure out is the reason behind the expression's classification as non-real—especially when the sole number of zero is real, despite not having an evident value.  This covers a few different things, so I was uncertain about what to make the title of these questions. I apologize for that. If anyone can answer, though, I'd be extremely grateful! I have searched the web a lot and could not find an answer that fits my situation. Here are two links that are quite contradictory:       My situation:  I've visited Portugal in December 2012 for 29 days on a Schengen visa valid from December 1st, 2012 to February 1st, 2013 for research purposes (I am a Ph.D. student). I want to visit Sweden from February 10th, 2013 to May 10th, 2013 (89 days). I have applied for a Schengen visa again (for research). How will the 90/180 rule work in my situation? How to delay or slowly loop commands? I found 11 questions like this on gamingSE already, but none of them have proper and up-to-date answers. So I'm creating this Q&amp;A:  How do you either activate a command x seconds/minutes/hours/… in the future or every x seconds/minutes/… in a loop?  Repeating command blocks and ticking functions execute 20 times per second, redstone is  in many situations and most of the extremely fancy solutions, like falling blocks in cobwebs, have broken over time or are needlessly complicated. Separator between command list and } The Bash Manual says   { list; }        Placing a list of commands between curly braces causes the list to be executed in the current shell context. No subshell is   created. The semicolon (or newline) following list is required.      The braces are reserved words, so they must be separated from the list   by blanks or other shell metacharacters.       The parentheses are operators, and are recognized as separate tokens   by the shell even if they are not separated from the list by   whitespace.   If I remove the semicolon, like this:  $ { date } &gt;    Why does it expect stdin input? A metacharacter is a character that separates words.  The semicolon and whitespace are both "shell metacharacters". Why can't whitespace separate words date and }? Why do we need a semicolon instead of a whitespace for separating the words? Ampere's law and external currents In Ampere's law, the current outside the curve taken is not included in the expression. Does it mean that the magnetic field calculated by using the law gives the contribution of only the currents crossing the area bounded by the curve? Is there anywhere within the Blender UI that displays the dimensionality &amp; bounding sets (e.g., all floats, floats in [0,1], floats in [0,255], etc) of arbitrary shader node inputs &amp; outputs?  I consistently find myself digging through stackexchange/the Blender docs/experimenting with less-than-equal-to to try to figure out what I need to divide by to normalize shader nodes' input/output values to within a specific range, or to center them at 0, etc. This seems like functionality that Blender's very rich UI might already have built into it, though, so I am wondering if I am just overlooking it somewhere.  As an example, I can do something like this, varying the threshold between 0, 0.5, and 1, and observing that in rendered view my sphere switches from all black to mixed black/white to all white, to convince myself that Blender's (Perlin) Noise Texture's Fac output naturally outputs floats in [0,1]:    But it seems odd that I should have to experiment, or search through docs or stackexchanges, to discover something like this. Is this information maybe already neatly displayed somewhere inside the Blender UI, and I just don't know where to look? Inverse metric in linearised gravity Can an ideal in a commutative integral domain be its own square? If $I$ is a non-zero proper ideal of a commutative integral domain, is it possible for $I$ to be its own square? Salesforce - user trigger not invoked when user role changes There are two ways to change user role. One is from user detail page, which invoke user trigger. I am facing issue where if user role is changed from ROLE hierarchy screen, then user trigger is not being invoked.  Any body know if there is written documentation which specifies this? or is it just my ORG having some setting to skip user trigger?   Below is screenshot of the screen from where it happens. Prove the inequality and limitation Suppose $\{a_k\}$ ,$\{b_k\}$ and $\{\xi_k\}$ are non negative, and for all $k\ge 0$ , we have $$a_{k+1}^2\le(a_k+b_k)^2-\xi_k^2$$   Prove   1.$$\sum_{i=1}^{k}\xi_i^2\le(a_1+\sum_{i=0}^kb_i)^2$$   2. If $\{b_k\}$ also satisfy $\sum_{k=0}^{\infty}b_k^2\lt+\infty $, then $$\lim_{k\to\infty}\frac{1}{k}\sum_{i=1}^k\xi_i^2=0$$   After doing this transformation:$$\xi_k^2\le(a_k+b_k)^2-a_{k+1}^2$$ $\Rightarrow$ $$\sum_{i=1}^{k}\xi_k^2\le(a_1+b_1-a_2)(a_1+b_1+a_2)+(a_2+b_2-a_3)(a_2+b_2+a_3)+\cdots(a_k+b_k-a_{k+1})(a_k+b_k+a_{k+1})$$ then I can't move forward any more. Is there anyway to modify stat information like mtime or ctime manually in Python or any language at all? Is there any way to specify a suggested filename when using data: URI?