I have some cron jobs set up to run, some of them each minute. I know I can log them to text files by simply putting php /path/to/file.php &gt; /var/logs/something.txt but can I do this every minute? The nature of the log's output means that the log file will be very small, but I don't know how to log each minute's output to a separate file.  Thanks
I'm setting up a Cronjob that will backup a MySQL database I have in my server, but I don't want it to keep overwriting the same file over and over again. Instead, I want to have an array of backups to choose from, done automatically. For example:  ## Cronjob, run May 21st, 2011: mysqldump -u username -ppasword database &gt; /path/to/file/21-03-2011.sql  ## SAME Conjob, run May 28th, 2011: mysqldump -u username -ppasword database &gt; /path/to/file/28-03-2011.sql   And so on.  Is there any way that I can use the system date and/or time as some kind of variable in my Cronjob? If not, what are your suggestions to accomplish the same?
Any suggestions for a good undergraduate introductory textbook to statistics? I am hoping you can give me some suggestions. I am teaching in a very diverse (made of minority groups) college and the students are mostly Psychology majors. Most students are fresh from high school but some of them are older returning students above 40. Most of the students have motivational problems and aversion to math. But I am still looking for a book that covers the basic curriculum: from descriptive to sampling and testing all the way to ANOVA, and all in the context of experimental methods. The department requires me to use SPSS in class, but I like the idea of building the analysis in a spreadsheet such as excel.  p.s. the other teachers use a book that I don't like because of the extensive reliance on computational formulae. I find using these computational formulas - rather than the more intuitive and computationally intensive formula that is consistent with the rational and basic algorithm- unintuitive, unnecessary and confusing. This is the book I refer to Essentials of Statistics for the Behavioral Sciences, 7th Edition Frederick J Gravetter State University of New York, Brockport Larry B. Wallnau State University of New York, Brockport ISBN-10: 049581220X Thank you for reading! How do I change the Google Play country? Can someone tell me how to change the country preference for Google Play? I have searched high and low but in most of the forums people ask you to go to Gmail settings -> edit profile and change the country there. But there is no place to change the country in settings! There is a something called place (which can be marked as current) but that has no impact on Google Play.  I don't want to circumvent country restrictions, I want to permanently change the country. So it's NOT a duplicate of . Is there a way to disable the hardware on/off switch for the Wireless interface? Show that if $ \ A \cup B = A$ and $ \ A\cap B = A$ then $ \ A = B$ Question:  Show that if $ \ A \cup B = A$ and $ \ A\cap  B = A$ then $ \ A = B$  My attempt:  Proof by contradiction:  Assume $ \ A \cup B = A$ and $ \ A\cap  B = A$ and $ \ A \neq B$   Case 1: $ \exists \ x \in A, x\notin B$  If $ x \in A \implies x\in A \cap B \implies x \in A \ and \  x\in B  \implies x\in B$, a contradiction.   Case 2: $ \exists \ x \in B, x\notin A$  If $ \ x \in B \implies x\in A \cup B \implies x\in A$, since $ \ A \cup B = A$. Contradiction.   Is this approach correct? Could someone please show me how to do a direct proof? Why don't we consider centrifugal force on a mass placed on earth? Let us say a block of mass is placed on the surface of earth. Then while drawing the forces on that body, we say:   Force $F = mg$ acting towards the center of Earth. Normal reaction $N$ offered by the surface of Earth.   If no other forces are acting, we say $F=N$. But what about the centrifugal force $m\omega^2R$ . Why don't we ever bring that into picture? What am I missing? Does "make offline" option in Google Maps works with applications that utilize Google Maps? In newer Google Maps I can make area available offline.  Do other applications that rely on Google Maps (utilize Google Maps Android API) use offline maps? How to explain the different forms of the Hamilton-Jacobi equation? In Arnold's Mathematical Methods of Classical Mechanics, he derives the Hamilton-Jacobi equation (HJE) using a generating function $S_1(Q, q)$ to get  $$ H\left(\frac{\partial S_1(Q, q)}{\partial q}, q, t \right) ~=~ K(Q, t). $$  However, this is different from what I've seen in other physics texts. For example, Goldstein uses the generating function $S_2(q, P, t)$ to get the equation  $$ H\left(\frac{\partial S_2(q, P, t)}{\partial q}, q, t\right) ~=~ - \frac{\partial S_2(q, P, t)}{\partial t}. $$  Why is there this difference? Are the two equations saying the same thing? How to look up a symbol or identify a letter from a math alphabet or other character? How can I send mail from an iPhone application I want to send an email from my iPhone application. I have heard that the iOS SDK doesn't have an email API. I don't want to use the following code because it will exit my application:  NSString *url = [NSString stringWithString: @"mailto:foo@example.com?cc=bar@example.com&amp;subject=Greetings%20from%20Cupertino!&amp;body=Wish%20you%20were%20here!"]; [[UIApplication sharedApplication] openURL: [NSURL URLWithString: url]];   So how can I send an email from my app? $\ker T\subset \ker S\Rightarrow S=rT$ when $S$ and $T$ are linear functionals Delay in approval leads to missing out on being awarded an "Explainer" badge How can I disable javascript popups/alerts in Chrome? Sorry if it's been asked. I've already found several solutions that aren't working. Not sure what I'm doing wrong.   I don't want to disable all javascript, only Javascript alert boxes. The ones that pop up and force you to click OK or X to close them.  I've found user scripts that claim to do this (example:  ). I've put chrome on the dev channel, start chrome with the --enable-user-scripts switch, the script shows up as installed.  But I still get the alert boxes.  An example alert box that isn't getting disabled is at  - put in any garbage word into the word validator on the right sidebar. You get a popup telling you it's not a word. SQL to find the number of distinct values in a column Lost reputation after answering my own question with bounty Timeline:  Asked a question, no (interesting) answers for two weeks  Set bounty on it this morning  Found the answer to my question two hours later. Answered my own question.  Bounty reputation is lost. It was not awarded to me, it was not returned to me (the 100 I invested).   Right now, I feel really stupid for answering my own bounty question.   If this is accepted behavior, then user should be warned - you are answering your own bounty question, your bounty reputation will be LOST. How to remove the handles from this faucet My bathroom faucet is leaking around the base of my right handle.  With previous faucets I've been able to use a set screw to loosen the handle and replace the washer.  With these, though, I can't seem to pop off the faucet handle.  Does anyone know how to remove this handle?  Does anyone know the brand of this faucet?  Update -- Nov 29th  I've already tried to get those cap ends off.  I tried to use some pliers and unscrew them, but couldn't remove it.  I tried taking a small flat head and popping off the ends.  Still nothing.  It doesn't seem like the come off.  I also tried unscrewing the handles, but they just don't see to turn for me.  Also there is definitely no set screw on the handles.  I've searched all around the faucet and found nothing indicating a set screw. I know there is a way to view all my questions in reverse chronological order from the PC by going to my profile. But I would like to do the same from the mobile app for Android. On Android in the left upper hand corner I can only see the latest answers to my posts, but I would be able to view all my posts. Why are ammeters used in series and voltmeters in parallel? I cannot make xmodmap run on login in Ubuntu 13.04. I have searched around, including in askubuntu and all answers I found do not work.  I have a file named .Xmodmap in my home folder which contains the desired mappings. If I run it manually it works fine, so there is no error there. In order to make it run on startup, I have tried:     Using various .xinitrc containing one of the following commands:      xmodmap .Xmodmap xmodmap ~/.Xmodmap   /usr/bin/xmodmap /home/NAME/.Xmodmap if [ -s ~/.Xmodmap ]; then xmodmap ~/.Xmodmap fi  Using .Xresources instead of .xinitrc with the same variations. Setting it as a startup application.   None of the above works in Ubuntu 13.04 (64-bit). I also saw a few ideas about globally changing the keyboard mappings, but most of them were not applicable in Ubuntu 13.04 (i.e. the corresponding files did not exist where specified) and I prefer not to touch the global settings anyway. Can you create an illusion of empty space? I've been thinking of various ways for a crafty Illusionist/Rogue to 'hide in plain sight' by essentially creating the cover that they want to hide behind.  Ideas include things like:   Create a wall that is 2.5ft closer than it really is and hide in said space Create some innocuous barrier or container and hide within it Create a 'sheet' that essentially has what an empty room looks like 'painted' on it, so someone walking past an open door would see an empty room.   From different discussions I've had, these all should work, but the one lingering one I have is, what if my illusion is simply 'empty space'?  If I were to create an illusion of empty space and then place myself in it, would I be essentially invisible?  What if I created an illusion that was partially-empty space, like a 5x5 cube of swiss cheese? Would it seem like there was a swiss cheese cube formed around my person or could my 'fake-empty-space-image' fill the holes?  Would my 'empty space' illusion simply need to work like the aforementioned 'sheet of what I expect you to see' in order to function (and thus most likely only work from limited viewing angles)? I am studying the function and characteristic of an op-amp to build a line-following robot with the schematics below. However, in many tutorials, the way to differentiate an inverting and non-inverting op-amp is by looking at the connection to ground via the inverting or non-inverting terminal.  However, in the schematics, the op-amp is considered to have connections to ground, thus in this case, how do I differentiate it then?  I may have understood the whole concept wrongly. Pls help!    EDIT: Please ignore the switch as it may have been drawn wrongly by the supplier.