How can I set my Ubuntu 12.04 LTS to boot to console without GUI?
How do I disable X at boot time so that the system boots in text mode?
How do you use a variable in a regular expression? I would like to create a String.replaceAll() method in JavaScript and I'm thinking that using a regex would be most terse way to do it.  However, I can't figure out how to pass a variable in to a regex.  I can do this already which will replace all the instances of "B" with "A".  "ABABAB".replace(/B/g, "A");   But I want to do something like this:  String.prototype.replaceAll = function(replaceThis, withThis) {     this.replace(/replaceThis/g, withThis); };   But obviously this will only replace the text "replaceThis"...so how do I pass this variable in to my regex string? Get selected text from a drop-down list (select box) using jQuery Removing files with strange names Possible Duplicate:          Somehow I ended up with a file named "-r".  How do I remove it?  rm -r doesn't work.  I tried 'rm -i `ls -a`' to step through the file names, but it didn't prompt me to delete this one.  Edit A very hacky approach was to use python's os.unlink function.  That worked, but I'm curious to hear other ways. Joda Time: How to get dates of weekdays on some date interval? i m using ubuntu 10.10. please tell me how to type in hindi fonts in open office word. please help Hom is a left-exact functor What happens if my flight out of the Schengen area is cancelled on the last day of my visa? Is it possible to hide curves' guides in edit mode? How do I put text over symbols? This is difficult for me to explain, but how do I put words over a symbol? For instance, I want to add words over an equal sign. Anyone know the command/syntax for that?  Also adding ^ doesn't cut it..., I want the text to appear ON TOP. Remove paint from the head tube I'm planning to build a new bike from scratch.  Part of that is buying a new frame, and possibly facing/reaming it. That's actually the part I'm scared of the most.  Fortunately, the brand I'm targeting, Surly, seems to do that in the factory. But as they state, there may be some paint left where it should not be:     Since Surly frames are faced prior to painting, it is possible to   shave the paint off the head tube and BB shell ends with a carpet   knife blade.  This usually results in an acceptable result, saving you   money, but we still recommend having it done the proper way to ensure   longest life from your components.   So what is the "proper way" to remove the extra paint, if the frame is properly reamed/faced already?  Should I choose not to do it the proper way, which components are going to suffer? I suppose at least the headset and bottom bracket, but could the frame suffer as well? Socket Tester all indicators light up I used the above GFCI/RCD (up to 250v) socket tester on the 240v black and red live wire of the US split phase ac power system. When I connect the ground, all indicator lights (3 red) got on indicating "Live/Grd Reverse, Missing GRD" although it is connected properly.  What is inside the socket tester? Does it have a live and neutral leg such that it should only be used for ac system with polarity? How about if you use it on the red and black 240v phase to phase? Why would all the indicators light become on (3 red lights)?  The following is the specs of it:  Specifications: Brand Name: HABOTEST Color: Black Material: Flame Retardant ABS Plug Type: US Voltage: 48V-250V 45-65Hz RCD Test: >30mA (EU/UK Plug) RCD Working Voltage: 220V±20V GFCI Test: >5mA (US Plug) GFCI Working Voltage: 110V±20V Voltage Measurement: 48V~250V / 45~65Hz    Accuracy: ±(2.0%+2) Working Environment: 0°C ~ 40°C, 20% ~75%RH Storage Environment: -10°C ~ 50°C, 20% ~80%RH Safety Rating: EN61010-1,-2-030, EN61326-1,CAT II 300V Item Size: 62 * 65 * 55mm / 2.4 * 2.6 * 2.2in Item Weight: UK 64g/2.3oz, EU 59g/2.1oz, US 53g / 1.9oz Package Size: 7.5 * 7.4 * 7.3cm / 3.0 * 2.9 * 2.9in Package Weight: UK 90g/3.2oz, EU 86g/3.0oz, US 79g / 2.8oz Notify close voters when a closed question gets edited As mentioned in , a question closed because it was not well-phrased is currently very unlikely to be reopened after an edit clarifying the issues. Those who voted to close should at least be asked to reconsider and reopen the question after such an edit. Regarding the `book`, `report`, and `article` document classes: what are the main differences? Looking for a 1000 most frequent english words Is there a free list of 1000 most frequent words used in everyday English? If there is a list with usage examples (as each of those words has multiple meanings for sure, not to cound phrasal verbs), it would be even greater.  Is there something alike, but with phrases? (E.g. 1000 most frequent phrases) How do I get the square root of a complex number? If I'm given a complex number (say $9 + 4i$), how do I calculate its square root? In case of shell-builtins (eg type itself):  $ type type type is a shell builtin  $ which type &lt;Doesn't return anything since it's a shell builtin, silently exits&gt;   In case of commands (normally) (eg python):  $ type python python is /usr/bin/python  $ which python /usr/bin/python   In case of which (which is a command located at /usr/bin/which)  $ type which which is hashed (/usr/bin/which) $ which which /usr/bin/which   Why does type which say that which is hashed? What is the significance of which being hashed and what does it actually mean? What to do when you discover a mistake in the archived copy of your PhD thesis? I've just defended my PhD in mathematics and started a postdoc. While working  on an improvement of one of the results of my thesis, I realized that there are several minor mistakes and a big bug in a proof that invalids a minor result in the thesis (about 3-4 pages out of 110). Unfortunately neither I nor my advisor or referees figured it out the mistake. Though the result is minor, it is announced in the introduction and the manuscript is on-line on an ArXiv-like server, so that I could publish a new version but not cancel the one on-line.   What is the best thing to do? Upload an errata? Upload a "revised" version of the thesis?  Publish a "revised version" of the thesis on my web-page?  Can this damage my future career, making me look not "reliable" as a researcher? Consider an irreducible but possibly periodic Markov chain on a finite state space with transition matrix $P$. We know there exists a unique stationary distribution $\pi$. If the Markov chain were aperiodic, we would have $P^n_{ij} \to \pi(j)$ as $n \to \infty$. This fails if the chain is periodic, but we have convergence of the Cesaro averages: $$\frac{1}{n}\sum_{k=1}^n P^k_{ij} \to \pi(j) \text{ as } n \to \infty.$$ Can anyone point me to a reference that states this fact? Every reference I've seen only considers convergence for aperiodic chains, or "fixes" periodicity by considering a lazy version of the chain. Alternatively, is there a simple way to obtain this result using the result for aperiodic chains? How do I know if a laptop will work with Ubuntu? I want to buy a laptop at some point in the near future, but not knowing beforehand whether it works with Ubuntu makes the whole operation risky and tiresome. I would like to know if there is some kind of official hardware database where I can enter the name of the laptop I'm interested in and see if it's 100% compatible out of the box, or in case it isn't what is it exactly that doesn't work (ideally also if there is a way to fix it).  Does Canonical have a project along these lines? (complex measures) $d\nu=d\lambda +f\,dm \Rightarrow d|\nu|=d|\lambda| +|f|\,dm$ and $f\in L^1(\nu)\Rightarrow f\in L^1(|\nu|)$ Two simple exercises on complex measures I don't know how to solve, from Folland's Real Analysis. I find it difficult to manipulate the definitions in computations. For context, if $\nu$ is a complex measure on $(X,\mathcal{M})$ then $|\nu|$ is defined as $d|\nu|=|g|\,d\mu$ where positive measure $\mu$ and $g\in L^1(\mu)$ are such that $\nu \ll \mu$ and $\nu = g\,d\mu$ (and in the textbook it's shown that this definition does not depend on the choice of $\mu$).     1) Let $\nu$ be a reguar complex Borel measure on $\mathbb{R}^n$, $m$ denote   Lebesgue measure, and   let $d\nu = d\lambda + f\,dm$ be its Lebesgue-Radon-Nikodym   representation. Then ("it is easily verified")   $d|\nu|=d|\lambda|+|f|\,dm$.      2) If $f\in L^1(\nu)$ then $f\in L^1(|\nu|)$. I was able to prove the   reverse implication, but not this one.   The definition of $|\nu|$ in the case of real signed measures (as $|\nu|=\nu^+ + \nu^-$) makes sense to me but I can't see intuitively into the definion of $|\nu|$ for complex measures as given in the textbook. Do you have any advice on this?  Thank you!