Bash command to open a system's terminal
What is the most portable method of launching a terminal emulator?
Sublime Command not working in SSH server on Ubuntu 14.04? Black holes and positive/negative-energy particles I was reading Brian Greene's "Hidden Reality" and came to the part about Hawking Radiation. Quantum jitters that occur near the event horizon of a black hole, which create both positive-energy particles and negative-energy particles, produce the so-called Hawking radiation. However, I do not understand why only the negative-energy particles are being absorbed into the black hole, while the positive-energy particles shoot outward. Shouldn't there be 50/50 chance that each type of particle is being absorbed by the black hole? Also, the book mentions that a negative-energy particle would appear to an observer inside the black hole as positive. Why? I have a blender file where a sphere is orbiting a force field. I want it to be more red when it's closer to the center, and more blue when it's further. I already have the math figured out, I just need to know how to get x/y coordinates in nodes.  Here's the file: $\bigcup \emptyset$ is defined but $\bigcap \emptyset$ is not. Why? Why does $\bigcup \emptyset = \emptyset$ but $\bigcap \emptyset$ is not defined?    If I had to guess, I'd say it's also equal to $\emptyset$. Any way to sync directory structure when the files are already on both sides? I have two drives with the same files, but the directory structure is totally different.  Is there any way to 'move' all the files on the destination side so that they match the structure of the source side? With a script perhaps?    For example, drive A has:    /foo/bar/123.txt /foo/bar/234.txt /foo/bar/dir/567.txt   Whereas drive B has:  /some/other/path/123.txt /bar/doo2/wow/234.txt /bar/doo/567.txt   The files in question are huge (800GB), so I don't want to re-copy them; I just want to sync the structure by creating the necessary directories and moving the files.  I was thinking of a recursive script that would find each source file on the destination, then move it to a matching directory, creating it if necessary. But -- that's beyond my abilities!  Another elegant solution was given here: I have a VF page built on Lightning Design system (LDS) framework. When I add the renderAs="PDF" attribute, pdf does not show the content with LDS CSS/Style.  Reference Link:   Note1: apex:page tag has all the usual attributes which is required for pdf *     (showHeader="false" sidebar="false" standardStylesheets="false"   docType="html-5.0" applyHtmlTag="false" applyBodyTag="false")   Note2: Salesforce supports external stylesheet. That is, CSS file stored in Static resource. Link of example:   I also copied the whole css content from the LDS CSS file (Path: 'assets/styles/salesforce-lightning-design-system-vf.min.css') and applied as inline CSS in VF page. But still, there is no luck.  My styleSheet is referred in VF page as below  apex:stylesheet value="{!URLFOR($Resource.SLDS221,      'assets/styles/salesforce-lightning-design-system-vf.min.css')}"   Page works absolutely fine if it is not rendered as PDF.  Any suggestions? we all study mathematics , and all of us learn mathematical methods to solve problems , we learn how to prove , how to think mathematically   but the question is, what is mathematics ? how can we define it as a branch of science ? Prove that the set of palindromes are not regular languages using the pumping lemma. Firstly I pick a language $xyz$ where $x = \epsilon$, $y = (abb)^{k}$, $z = (bba)^{k}$ where $|y| \ge$ the number of states in the automaton representing my language. Then $xyz = (abb)^k(bba)^k$ is a palindrome.  Now I split $y$ into $uvw$, where $v \ne \epsilon$ contains a state visited more  than once. If the language is regular then $xuv^iwz$ is within the language $\forall i \ge 0$.  I choose $i = 2$, then $uv^2w = (abb)^n$ where $n &gt; k$.  Then $xuv^2wz = (abb)^n(bba)^k$ where $n &gt; k$, which is not a palindrome.   Firstly, is my reasoning for this particular proof correct?  I'm unsure about how to properly apply the pumping lemma to this problem. And secondly the question asks me to state a proof for palindromes in general, whereas I only attempted to prove it for a single case. Is there an example I can choose which proves the conjecture for all palindromes? I assume not, seeing as I can't think of how that could be represented using regular expressions. The Windows Domain I manage has hundreds of computer names which I don't recognise and I'd like to remove old ones which aren't in use before trying to track down the misnamed ones.  Is there someway to see when the last time a machine logged onto the network? Either via dhcpd or a user login event or something else. Punctuation of a Direct Quote Is any particular punctuation necessary when a quotation is the subject of a sentence? For example, in the sentence below, should there be a comma after export? Or anything else?     "Laughter is America's most important export" is a well-known quote of Walt Disney's. Proving by induction that $ \sum_{k=0}^n{n \choose k} = 2^n$ What are the regulations for transporting medication abroad? This is in reference to medications, both prescription and non-prescription, not illicit drugs. Since the legality may vary on country, let's say a round trip from the US to Singapore, as an example.  When travelling with prescription medication, I am aware that you are supposed to bring your prescription with you. What about over-the-counter medication, such as Tylenol/aspirin? How about medication which is restricted or prescription-only in one country, yet available OTC in another (think Viagra)? How could I go about setting the 'above' and 'below' vspaces around the equation environment?  If the same could be done for the subequations or gather environments, this would be a bonus. I've noticed an interesting phenomenon in the user interfaces of many famous applications, they're moving away from the glossy complex to a more dull and bare minimum design.  Why the sudden change? It also appears that most of these companies have adopted this design around the same time, was that linked to some new study?  Examples: Can a finite sum of square roots be an integer? Can a sum of a finite number of square roots of integers be an integer? If yes can a sum of two square roots of integers be an integer?  The square roots need to be irrational. How to align floating point variables in Latex3 I would like to have the variables (defined in Latex3) aligned in a table with the decimal point. Of course, without using the &quot;trial and error&quot; extra space &quot;,&quot;. Is there any possibility? Thank you very much. \documentclass{article} \usepackage{xparse} \usepackage[version=4]{mhchem}  \usepackage{siunitx,booktabs}  % \ExplSyntaxOn \NewDocumentCommand{\calcnumd}{o m}   {\IfValueTF{#1}      {\num[round-mode = figures, round-precision = #1, round-integer-to-decimal]{\fp_to_decimal:n{#2}}}      {\num{\fp_to_decimal:n{#2}}}   } % data \fp_set:Nn \dhfbiox {33.18} \fp_set:Nn \dhftetrox {9.16} \fp_set:Nn \dgfbiox {51.31} \fp_set:Nn \dgftetrox {97.89} \fp_set:Nn \cpbiox {37.20} \fp_set:Nn \cptetrox {77.28} % calculations % \ExplSyntaxOff % \begin{document}  \begin{center} \begin{tabular}{l|ccc}    &amp; $\Delta_f H^{\ominus}$ &amp; $\Delta_f G^{\ominus}$ &amp; $C_P$ \\    &amp; \si{\kilo\joule\per\mole} &amp; \si{\kilo\joule\per\mole} &amp; \si{\joule\per\kelvin\per\mole} \\ \midrule \ce{NO2} &amp; \calcnumd{\dhfbiox} &amp; \calcnumd{\dgfbiox} &amp; \calcnumd[4]{\cpbiox} \\ \ce{N2O4} &amp; \,\,\,\calcnumd{\dhftetrox} &amp; \calcnumd{\dgftetrox} &amp; \calcnumd{\cptetrox} \\ \bottomrule \end{tabular} \end{center}  \end{document} Complex numbers equation: $z^4 = -16$ Are users notified when their questions are reopened? Do users get notified when their question is reopened? I know there are no notifications , and that makes sense because 1) you assume the user is paying attention to their open, unanswered question, and they'll probably notice it's been put on hold and 2) it follows with the SE policy of (in general) not sending notifications for negative events.  However a reopening is a good thing, and once a question is closed it becomes less likely that the OP will be coming back to check on it often (so they might not notice the reopening otherwise). If there are not reopen notifications, why not? Or can we add them? Find the infinite sum of the series $\sum_{n=1}^\infty \frac{1}{n^2 +1}$ Share the clipboard between bash and X11 In  the top answer shows how to copy text that has been previously selected with the mouse on a gnome-terminal, to the clipboard in X11.  My question is: Say I copy a piece of text from the terminal using bash set-mark and copy keyboard shortcuts (i.e. set-mark + M-w). Is it possible to share this clipboard with X11?   EDIT: In the original question, I talked about sharing the clipboard with GNOME, but as Gilles points out below, GNOME doesn't specifically have a clipboard (it's general to X), so I have updated the question.