bash variable with quotes and percentage
How can we run a command stored in a variable?
When is it appropriate to end a question without a question mark? What does the term $\mathcal O(\epsilon^2)$ mean? I'm trying to prove the following statements in Folland's book.  Let $(X,\mathcal{M},\mu)$ be a measure space. If $f_n\to f$ in measure and $g_n\to g$ in measure, then $f_n+g_n\to f+g$ in measure and $f_ng_n\to fg$ in measure (in this last case, assume $\mu(X)&lt;\infty$).  The first one is already done, but the second one is giving me trouble.   My attempt: We can take subsequences $f_{n_k}$ and $g_{n_k}$ such that $f_{n_k}\to f$ a.e. and $g_{n_k}\to g$ a.e. In this case, we know that $f_{n_k}g_{n_k}\to fg$ a.e. Note that $\mu(X)&lt;\infty$, so we can use Egoroff's theorem to conclude that $f_{n_k}g_{n_k}\to fg$ almost uniformly. Finally, almost uniform convergence implies convergence in measure, therefore $f_{n_k}g_{n_k}\to fg$ in measure.   The problem is that I just have convergence in measure for some subsequence of $f_ng_n$ and I need convergence in measure for the whole sequence. Also I don't know if using Egoroff's theorem is unnecessary, if this is the case, I would appreciate to see some more elementary prove.  Detail: We say that $f_n\to f$ almost uniformly if for every $\varepsilon &gt; 0$ there is some $E\subset X$ measurable, such that $\mu(E) &lt;\varepsilon$ and $f_n\to f$ uniformly on $E^c$.  Thank you! Ambiguity of “not.... because” You are not hired because you are qualified.   I think this means you are hired but it is not because you are qualified. But I think this can  also means you are not hired, and the reason for it is that you are qualified.   Does this ambiguity really exist or do I mistake anything? Since canonical is  Ubuntu One, what are the possible alternatives?  I currently use Ubuntu One as a backup service for my Documents folder and various other folders I deem important. Of course I have backups on an external hard drive as well, but nevertheless, I find Ubuntu One to be very useful. What I'm especially looking for is a cloud service that does not need a special folder (such as a dropbox or google drive folder); something that is able to integrate into my own file system and syncs just any folder I want to.   I am aware that this question is rather subjective, but I do guess many people who have used Ubuntu One are now in the dark. S(x), which stands for “x is a surgeon”  P(x, y), which stands for “x is a patient of y”  R(x), which stands for “x recovers”  H(x), which stands for “x is happy”  1>"A surgeon with no patients is happy" means: for any person xx, if xx is a surgeon and there is no person yy for which yy is a patient of xx, then xx is happy.  2> "A surgeon is happy if all her patients recover" means: for any person xx, if xx is a surgeon and - if for every person yy for which yy is a patient of xx, we have that yy recovers - then xx is happy.  I have these as solution:  1:∀(x) ( S(x)∧ ∀(y)P(y,x) → H(x) ) 2: ∀(x) [ { S(x)∧ (∀(y)P(y,x) ∧ R(y)) } → H(x)]  Are these okay?  And how do prove that 1 follows from 2 by resolution (not by drawing a truth table)? ViewPager as a circular queue / wrapping What causes the expansion of space? I'd like to add an invisible watermark to each PDF document that I produce so that in case it leaks, I know where it leaked from. Anyone knows what would a good way for an invisible watermark be in a PDF document and how to add one? This appears to be a css bug which (I think) has recently been introduced. It's most visible when viewing questions on Stack Exchange sites using mobile devices (the full site with responsiveness, not the mobile site) but can easily be reproduced by resizing a browser window on a question where the combined width of the tags is large. A couple of example questions show this behaviour:  On Meta Stack Overflow:   On Meta Stack Exchange:     Using the Meta Stack Overflow question to demonstrate (as the total width of the tags is larger):  At 1100px, the tags just about fit into their containing div.     At 800px, the tags appear on top of related questions:     At 450px, the tags are now wider than the view (the last tag is completely off the screen), causing scroll bars to appear:      This doesn't happen to lists of questions - the tags flow onto multiple lines:     Reproduced on: { Firefox 81, Chrome 84, Edge 84 } on Windows 10, and Chrome 85 on Android 11. How do I get the first element from an IEnumerable in .net? I often want to grab the first element of an IEnumerable&lt;T&gt; in .net, and I haven't found a nice way to do it.  The best I've come up with is:  foreach(Elem e in enumerable) {   // do something with e   break; }   Yuck!  So, is there a nice way to do this? How can I get the current working directory? I want to have a script that takes the current working directory to a variable. The section that needs the directory is like this dir = pwd. It just prints pwd how do I get the current working directory into a variable? I want to know, is there a way to make a tungsten lightbulbs filament withstand a mass amount of thermal shock while still producing a vast amount of heat? Prove that $\overline {A^\complement} = (A°)^\complement $   To show that $\overline {A^\complement} \subseteq  (A°)^\complement$   We first show $A^\complement \subseteq  (A°)^\complement ...(*) $  We know that since $ A°\subseteq A \qquad (*)$ is automatically follows .  The part I didn't understand is the following:     Then we conclude that since $ (A°)^\complement$ is closed    $\therefore \overline {A^\complement} \subseteq  (A°)^\complement$ Select all contents of textbox when it receives focus (Vanilla JS or jQuery) What is a Vanilla JS or jQuery solution that will select all of the contents of a textbox when the textbox receives focus? Why do sunbeams diverge even though the sun is much more than a few kilometers away? Consider this picture of sun beams streaming onto the valley through the clouds.    Given that the valley is only (at a guess) 3km wide, with simple trigonometry and the angles of the beams, this gives the result that the position of the light source is being a few tens of km away at most.   What is wrong with the analysis? I have already dual systems : Windows 7 and Ubuntu installed on my laptop. The Windows 7 had been installed when I bought this laptop, and I don't have a CD.  I just installed VitrualBox under Ubuntu, hoping that I could install another Windows in this virtual machine, so that I could run some applications of Windows even under Ubuntu.  But it seems that I need a CD or ISO of Windows to boot inside this virtual machine. Otherwise, there is an error: FATAL: No bootable medium found! System halted. My question is where I could find a CD or ISO?  At the moment, I am downloading ISO from this , but do not know if it will work. By the way, I am not sure if I should pick the 32-bit or 64-bit? As my CPU is 64-bit but my Ubuntu is i386.  Could anyone help? Thank you very much. Make \cite{my reference} show name and year I am trying to figure out how to make author's name and year show up every time I make a reference.  For example:  my_bibtex.bib has this entry:  @article{Franklin1999,  author = {Franklin Allen and Risto Karjalainen}, title = {Using genetic algorithms to find technical trading rules}, year = {1999}, volume = {51}, pages = {245-271}, journal = {Journal of Financial Economics}  }   If in my_paper.tex I use this line:  Important result has been found by \cite{Franklin1999}   My output looks like:  Important result has been found by [1]   But I want it too look like:  Important result has been found by Franklin 1999   I there a way to do it?  My bibliographystyle is set to plain  \bibliographystyle{plain}  \bibliography{my_bibtex} The Stack Imgur service is no longer resizing images correctly Is it correct to say user accounts or users account when referring to the accounts any user has on a site like this one?  In general, in the case of a noun that is used as adjective for the noun that follows, is it better to use &lt;plural-noun&gt; &lt;singular-noun&gt; or &lt;singular-noun&gt; &lt;plural-noun&gt;?