Unable to start cron service
Why is my crontab not working, and how can I troubleshoot it?
What happens if you use Polyjuice potion after saving hair or nails? Suppose you cut a five year old's hair, save it for 10 years, and then use it for a Polyjuice transformation. What age do you turn into: The toddler or the teenager? I have several files with the same base filename. I'd like to remove all but one  foo.org #keep foo.tex #delete foo.fls #delete foo.bib #delete etc   If I didn't need to keep one, I know I could use rm foo.*.    demonstrates ^ to negate a match. Through trial and error, I was able to find that  rm foo.*[^org]   does what I need, but I don't really understand the syntax.   Also, while not a limitation in my use case, I think this pattern also ignores foo.o and foo.or. How does this pattern work, and what would a glob that ignores only foo.org look like? What's the difference between the nvidia-current, and nvidia-current-updates packages? What's the difference between the , and  packages?  The former has a higher version number, and the description of the packages are the same.    Which do I use? Which is the most recent one What's the purpose of this split packaging? Are all limits solvable without L'Hôpital Rule or Series Expansion Is it always possible to find the limit of a function without using  or ?  For example,   $$\lim_{x\to0}\frac{\tan x-x}{x^3}$$  $$\lim_{x\to0}\frac{\sin x-x}{x^3}$$  $$\lim_{x\to0}\frac{\ln(1+x)-x}{x^2}$$  $$\lim_{x\to0}\frac{e^x-x-1}{x^2}$$  $$\lim_{x\to0}\frac{\sin^{-1}x-x}{x^3}$$  $$\lim_{x\to0}\frac{\tan^{-1}x-x}{x^3}$$ Reading a bit about recent Monica Cellio related posts, I am afraid that I may be using a language that is a lot like English, but might not be the Stack-Exchange-approved version of English. For example, my English has had a certain gender-neutral pronoun in living use for centuries. That pronoun is used throughout the literature written in this version of English. It is used in the English I was taught as a grammar school student and later as a graduate student working on a master's thesis. I believe that this English is good enough to communicate about topics relevant to the various Stack Exchange sites.  The last thing I want from Stack Exchange is to be booted out because I slip up and accidentally use the language that has served me so well for a lifetime.  The topics discussed on Stack Overflow (I almost referred to it as a "sister site;" would that have been allowed? "mother site?" Good thing I didn't?) are often centered on languages which have formal descriptions.  Where is the formal description of the language that is to be used on Stack Exchange?     Strive not with a man without cause, if he have done thee no harm.      He shall die without instruction; and in the greatness of his folly he shall go astray. I am wondering if my proof is correct? Thank you for whoever willing to take a look at it for me.     Proof $\liminf E_k \subset \limsup E_k $   If $\{E_k\}_{k=1}^\infty$ is a sequence of sets, we define \begin{align*} \limsup E_k &amp; = \bigcap_{j=1}^\infty\left(\bigcup_{k=j}^\infty E_k\right)\\ &amp;= \bigcap_{j=1}^\infty(E_j \cup E_{j+1} \cup \cdots)\\ &amp;= (E_1 \cup E_2 \cup \cdots) \cap (E_2 \cup E_3 \cup \cdots) \cap \cdots. \end{align*}  Therefore, $\limsup E_k$ consists of those points in $\mathbb{R}^n$ which belong to infinitely many $E_k$. \begin{align*} \liminf E_k &amp; = \bigcup_{j=1}^\infty\left(\bigcap_{k=j}^\infty E_k\right)\\ &amp;= \bigcup_{j=1}^\infty(E_j \cap E_{j+1} \cap \cdots)\\ &amp;= (E_1 \cap E_2 \cap \cdots) \cup (E_2 \cap E_3 \cap \cdots) \cup \cdots. \end{align*} Therefore, $\liminf E_k$ consists of those points in $\mathbb{R}^n$ which belong to all $E_k$ for $k \geq k_0$.  Now consider $x \in \liminf E_k$, then $x \in E_1 \cap E_2 \cap \cdots$, or $x \in E_2 \cap E_3 \cap \cdots$ and so on, that is to say, $x \in E_{k_0} \cup E_{k_0+1} \cup \dots$ for some $k_0$. More specifically, $x \in E_k \forall k \geq k_0$. Therefore, $x \in (E_1 \cup E_2 \cup \cdots) \cap (E_2 \cup E_3 \cup \cdots) \cap \cdots$, so we showed $x \in \limsup E_k$. Transit visa at Istanbul Airport, Turkey, during a Turkish Airlines arranged stopover? Do I need a transit visa at Istanbul Airport to enter Istanbul for city sightseeing or hotel accommodation?. All services provided free by the Turkish Airline. I am Nigerian citizen and booked Turkish Airline flight to Nigeria with 12hours layover at Istanbul Airport. Cycles: How do I exclude the Environment Texture from reflections? How do I count the number of occurrences of a char in a String? Why does the order in which libraries are linked sometimes cause errors in GCC? Why does the order in which libraries are linked sometimes cause errors in GCC? Understanding Lasso Regression's sparsity geometrically Whenever someone writes about Lasso and Ridge Regression thy draw this diagram with the circle or with the diamond.    In the case of the diamond (Lasso regression) it is then always stated that Lasso forces one of the coefficients to 0. Therefor it introduces sparsity. I understand it somehow, but whenever I see the diagram my doubts return. Why couldn't one just draw it like this:    Obviously none of the coefficients is forced to zero in this case. Both can take number between -1 and 1. What am I missing? My drawing has to be wrong, but I don't get it why they always draw so that it hits $\beta_1=0$  Edit:  Just found this quote:     However, the lasso constraint has corners at each of the axes and so the ellipse will often intersect the constraint region at an axis   Is that it? It will intersect often with the constraint region, but it doesn't have to? Can't wrap my head around it. I can only imagine that in higher dimensional cases hitting a corner becomes more likely or even inevitable. Cant find my harddrives in ubuntu installation? Excel "if-then" formula IF(B4-40&lt;0,0,(B4-40))   Above is my formula to show only positive numbers above 40 in the given cell. If my hours are, let's say, 35, I do not want a value of -5; I want the cell value to be 0. Why is this not working? Many C++ books contain example code like this...  std::cout &lt;&lt; "Test line" &lt;&lt; std::endl;   ...so I've always done that too. But I've seen a lot of code from working developers like this instead:  std::cout &lt;&lt; "Test line\n";   Is there a technical reason to prefer one over the other, or is it just a matter of coding style? How to prove wave nature of large object? Can anyone point me to a reference (preferably either something online or something a small liberal arts school would be likely to have in its library) that goes through a derivation of the minimum uncertainty wavefunction in more detail than in the Griffiths?  Edit I've moved the second part of my original question to a separate post: R/mgcv: Why do te() and ti() tensor products produce different surfaces? To reopen a closed question,  must agree that the question is suitable for the site and cast votes to reopen the question. But:  How does one actually vote to reopen? Is there a reputation level that you must have before you can see this function? Or do I just leave a comment along the lines of, &quot;I vote to reopen&quot;? What happens if someone with less than 3000 reputation leaves a comment that they wish to vote to reopen? How can one draw attention to their closed questions? Is it done via a posting new question? Or do you edit the closed question?   Related:  For more information, see &quot;&quot; in the . Let f(x) be a  polynomial satisfying $\lim_{x \to\infty} \frac{x^4f(x)}{x^8+1}=3,$  $f(2)=5 $ and $f(3)=10$, $f(-1)=2$ and $f(-6)=37$ . And then there are some question related to this. In the solution it is given that according to the given information, $f(x)$ is a polynomial of degree 4 with leading coefficient 3. $f(x)=3(x-2)(x-3)(x+1)(x+6)+(x^2+1)$ Now what i think is that he got the coefficient 3 using the limits and the rest of the terms$[(x-2)(x-3)(x+1)(x+6)]$ from the respective $f(x)$ values from what was given and also the $(x^2+1)$ was added for the remainders, as they satisfy all the values that have been given to us in the question. I just wanted to know if my approach is right? or is there another elegant way to do it?. Sometimes I need to write text and then pipe that text into another command. My usual workflow goes something like this:   vim # I edit and save my file as file.txt cat file.txt | pandoc -o file.pdf # pandoc is an example  rm file.txt   I find this cumbersome and seeking to learn bash scripting I'd like to make the process much simpler by writing a command which fires open an editor and when the editor closes pipe the output of the editor to stdout.  Then I'd be able to run the command as quickedit | pandoc -o file.pdf.   I'm not sure how this would work. I already wrote a function to automate this by following the exact workflow above plus some additions. It generates a random string to act as a filename and passes that to vim when the function is invoked. When the user exits vim by saving the file, the function prints the file to the console and then deletes the file.   function quickedit {     filename="$(cat /dev/urandom | env LC_CTYPE=C tr -cd 'a-f0-9' | head -c 32)"     vim $filename     cat $filename     rm $filename } # The problem: # =&gt; Vim: Warning: Output is not to a terminal   The problem I soon encountered is that when I do something like quickedit | command vim itself can't be used as an editor because all output is constrained to the pipe.   I'm wondering if there are any workarounds to this, so that I could pipe the output of my quickedit function. The suboptimal alternative is to fire up a separate editor, say sublime text, but I really want to stay in the terminal.