What linux shell command returns a part of a string?
Extract substring in Bash
Function $f(z)$ is holomorphic at least within the unit disk.   If for all arguments $|z|&lt;1$ we have $|f(z)| \le 1$, and there exists a zero of order $n$ at $z=z_0$, then show that $|f(0)| \le |z_0|^n$.  How should I tackle this problem? Can it be generalized if for $|z|&lt;R$ we have $|f(z)| \le M$ ?    So far I only understand that there exists a holomorphic $g(z)$ with $g(z_0) \ne 0$ such that $f(z) = (z-z_0)^n g(z)$,then $|f(z)| = |z-z_0|^n |g(z)| \le 1$ and moreover $|f(0)| = |z_0|^n |g(0)|$, but that doesn't seem useful since apparently I know too little about $g(z)$. In particular why should $|g(0)| \le 1$? Python rounding error with float numbers Show that the congruence $x^{p-1} \equiv 1 \pmod {p^2}$ has precisely $p-1$ solutions modulo $p^2$ Let $p$ be a prime number. Show that the congruence $x^{p-1} \equiv 1 \pmod {p^2}$ has precisely $p-1$ solutions modulo $p^2$  I know the statment above is true for modulo $p$, but how is this imply to modulo $p^2$ Types in MySQL: BigInt(20) vs Int(20) Converting MultiLinestring to Linestring with PostGIS I have a multiline string and want to convert it to a linestring in order to use some functions that only work with linestrings. I used ST_Dump() and got a collection of my geometries. If I merge them back together, I still get the multilinestring. Should I get the Npoints and combine them together or something, in order to end up with a simple linestring? ST_LineMerge() also does not work on my multilinestring, it returns the same. my example,  MULTILINESTRING((-3.16420835153456 55.9269166007097,-3.164222 55.926918),(-3.1642070167833 55.9269296196706,-3.16421351659546 55.9268662214904),(-3.16421351659546 55.9268662214904,-3.16421636372824 55.9268384509897),(-3.16421636372824 55.9268384509897,-3.16422182573761 55.9267851753802),(-3.16422182573761 55.9267851753802,-3.16422870102352 55.926718114886),(-3.16422870102352 55.926718114886,-3.16423309121073 55.926675293667),(-3.16423309121073 55.926675293667,-3.16423565148822 55.9266503211093),(-3.16423565148822 55.9266503211093,-3.16424103159897 55.9265978443265),(-3.16424103159897 55.9265978443265,-3.16424680776317 55.9265415044985),(-3.16424680776317 55.9265415044985,-3.16425267254583 55.9264843002995),(-3.16425267254583 55.9264843002995,-3.16425541048045 55.9264575949012),(-3.16425541048045 55.9264575949012,-3.16426111146586 55.9264019883556),(-3.16426111146586 55.9264019883556,-3.1642667032531 55.9263474469124),(-3.1642667032531 55.9263474469124,-3.16426957768543 55.9263194101362),(-3.16426957768543 55.9263194101362,-3.16427488261739 55.9262676666359),(-3.16427488261739 55.9262676666359,-3.16428009893088 55.9262167875066),(-3.16428009893088 55.9262167875066,-3.164282741107 55.9261910161221),(-3.1642875546472 55.9261440655823,-3.164282741107 55.9261910161221),(-3.1642875546472 55.9261440655823,-3.16429466890915 55.9260746741522),(-3.16429466890915 55.9260746741522,-3.16430092974527 55.9260136069079),(-3.16430092974527 55.9260136069079,-3.16430822838418 55.9259424170929),(-3.16430822838418 55.9259424170929,-3.16431547242401 55.925871759829),(-3.16431547242401 55.925871759829,-3.16431448732505 55.9258328901507),(-3.16431770120536 55.9257327846001,-3.16431547242401 55.925871759829),(-3.164339 55.925777,-3.16431770120536 55.9257327846001)) What determines which frames are inertial frames? How to delete blank lines starting from line 5 I have this:  sed -i '/^$/d' temp_spec.rb   which is stripping blank lines and works well.  How can I make it only do this for lines 5-999 (or ideally 5 to end-of-file).  I tried:  sed -n5,999 -i '/^$/d' temp_spec.rb sed '5,999!d/^$/d' temp_spec.rb   but neither worked (no errors). Can't redirect cut output Screen brightness isn't taking effect on a Lenovo Z570 My Lenovo Z570 has two GPU's, nVidia and Intell. Brightness control has no effect what so ever over the screen brightness, and because I've had some major issues in the past when I was trying to fiddle with nVidia drivers and settings, and I wanna be cautious now. I haven't find similar questions referring 14.04 LTS with similar configuration as mine.   I've read that it could be fixed by adding/changing content in xorg.conf but when I run  sudo gedit /etc/X11/xorg.conf   the file comes out to be absolutely empty. What do I need to do, what do I need to add to it and not get my laptop screwed with a black screen again? One of the ways I quickly rename files in Windows is   F2 &gt; Rename &gt; Tab (to next file) &gt; Rename ...   But in Ubuntu/Nautilus, I can't tab to next file. But being on Linux, I think there must be a command line alternative.  However, sometimes, I may want more control over how to rename specific files. In that case, perhaps its better to be able to tab to the next file How can I avoid SSH's host verification for known hosts? I'm using Microsoft Word 2010 and I worked in a word-2003 compatible document (.doc). After hours of working, I selected a half of text and did Ctrl+X to copy it into another document. Surprising, after closing the current document and opening a new one and pressing Ctrl+V, nothing happened. After closing original document, ms word asked me if I want to save the clipboard buffer and I pressed No, as I didn't knew that MS Word has it's own clipboard.  Is there a way to recover that text that was "cutten" from original document and never "pasted" to the new one? The PC was not rebooted so i guess all my temp files are here. We've been talking a lot about the efficacy of community self-evaluations lately, both internally on the Community Team and out in the open . Lots of ideas were tossed around, but the underlying theme of these discussions has been that site self-evaluations are not useful in their current form. The review queue format hampers discussion, the meta thread posted by the Community user is trivially ignored, and the sample question size is far too small to be useful, but big enough to be non-trivial for participants. They also don't provide much in the way of useful information to community managers behind the scenes.  So we're going to shut them down this week, and we'll be using the time it saves us to digest the ideas y'all have thrown out in the previous discussions and figure out where to go from here.   I'll be going over the previous threads with a fine-toothed comb to try and suss out what worked well and what was broken and determine a more useful mechanism - if one is required at all. I'd also welcome continued suggestions from the communities about how to continue capturing what the evals accidentally did right - encouraging communities to stop and examine how they're doing at somewhat regular intervals.   So: if you have ideas on how to get communities to monitor their own Q&amp;A quality and get a little introspective, feel free to sound off in the answers.  Update: with a creative application of per-site feature toggles, we've shut down evaluations except on a handful of sites where they're currently running. Once those evaluations run their course, no new ones will be started anywhere on the network. I am a new user for Ubuntu. I downloaded 13.10 yesterday and made a bootable USB with universal USB installer on my Lenovo IdeaPad Z580 laptop which is now using UEFI; everything appeared OK.  When I booted from the LiveUSB I got the choices of trying or installing Ubuntu but both of them keep giving me these error:  [ 1.929082] kernel panic-not syncing vfs unable to mount root fs on unknown-block (0.0)   Please tell me what is going wrong? Prevent applications from opening browser Is there a free application out there that will intercept requests from applications to open a URL and prompt me as to whether or not I want the URL to be opened? (For instance, after Adobe Reader installs, it opens its website to get feedback about the install process.)  Ideally, it would be lightweight software for just this task, but if a larger firewall/security app provides this feature, that would be acceptable.  I'm using windows 7 32-bit.  As stating in a comment below, the idea is that you don't want the browser to open (assume it's not already running), so an extension (e.g. for Chrome, ffox) wouldn't be relevant. Subdivision Surface not making things smooth as they are in the tutorial I am following Torus object stretched in array curve modifier I have a chain object. And i have a curve it follows. I got it to work for following curve, but chain object is not circles but both parts are more like stretched circles (ovals). Object i made with 2 toruses one rotated 90 degrees and then joined them together. I tried single torus too. But same issue. on a curve it just looks stretched oval. What can be the issue?   Thanks Is there an easy way to convert a number to a word in PHP? In PHP, is there an easy way to convert a number to a word? For instance, 27 to twenty-seven. Some three-digit (incl. minus sign) vote count still doesn't display properly Related:      As the title says...    The Android app version is 0.1.58.  Here is my experimental results:   Vote counts >= 200 that I've tried seems to be fine Vote count == 241 has problem, 242 doesn't Vote counts which matches /^1[012345689][0-9]$/ seems to be having problem (may be overgeneralized) Vote count == -36 definitely has problem   Note that this is not a tablet, but a 4-inch mdpi phone, of 480x854px. Can XeLaTeX generate bold and italic font styles for typefaces that lack them? I use XeLaTeX in order to have easy access to fonts installed on my operating system, and Chinese in particular. Some of the Latin typefaces most pleasing to my eye do not have bold or italic font styles, and I wonder if XeLaTeX can remedy that.  I'm aware of the FakeBold and FakeSlant transformations within the fontspec package, but I'd be glad to know of a more attractive process, if there is one. (The specification, v2.1f, says, "Please don’t overuse these features; they are not a good alternative to having the real shapes.")