Let's assume I have a text file with a list of dates (dd.mm.yyyy).  01.01.2020 01.03.2020 01.01.2019   How do I sort them out? (oldest to newest in a "from top to bottom" fashion)?
in a file containing :  ... 18-11-2018:othercharacters 10-11-2018:othercharacters 03-10-2018:othercharacters 30-10-2018:othercharacters 27-09-2018:othercharacters 03-12-2018:othercharacters ...   the command :  sort -t- -k2 -k1    does not sort by date, what am I missing ?
How to handle ordinal categorical variable as independent variable I am using a logit model. My dependent variable is binary. However I have an independent variable which is categorical and contains the responses: 1.very good, 2.good, 3.average, 4.poor and 5.very poor. So, it is ordinal ("quantitative categorical"). I am not sure how to handle this in the model. I am using gretl.  [Note from @ttnphns: Although the question says the model is logit (because the dependent is categorical), the crucial issue - ordinal independent variables - is basically alike, be the dependent categorical or quantitative. Therefore the question is equally relevant to, say, linear regression too - as it is to logistic regression or other logit model.] Use induction to prove a product of sums of squares is a sum of squares How many Shutter Clicks on a New Camera considered normal?    I purchased a quotes new Nikon D750 and checked the shutter count and it has 264 Shutter Clik count on it.    Is that suspect of a returned purchase or used camera? How to mount a virtual hard disk? Is it possible to mount a virtual hard disk (VHD, HDD, VDI, VMDK) on Ubuntu? How can this be done? You are a pie maker and you are holding a fair to display your pies. You have 1000 pies. You have 10 workers to help you. The fair is in two hours. Unfortunately you discover that a rival pie maker has poisoned one of your pies with a form of norovirus that makes people violently ill one and a half hours after even consuming a tiny bit of it. You know if any single person who visits your fair gets ill, your business will collapse but you need all the non poisoned pies for the fair. You can take small samples from the pies without spoiling them and your workers are prepared to do anything to help you. How do you find the poisoned pie? Problem with solving systems of linear congruence of two variables The problem I am given is finding a solution to the following pair of equations:  $3x + 4y$ $\equiv$ $5$ $mod$ $13$  $2x + 5y$ $\equiv$ $7$ $mod$ $13$  By reading the methodology here:   Since the modulos in my problem are also the same, I am able to use substitution, but this leaves fractions in my expressions.  I then used matrix multiplication as follows:  $\begin{bmatrix} 3 &amp; 4\\ 2 &amp; 5\end{bmatrix}$ $\begin{bmatrix}\ x\\ y\end{bmatrix}$ = $\begin{bmatrix}\ 5\\ 7\end{bmatrix}$   And solving this also gives me a matrix with fractions, so I am a bit lost on how to solve this problem.  Any help is appreciated. Thank you very much. What is the limit of:  $$\lim_{n\to \infty} \frac{n^1+\dots+n^n}{1^n+\dots+n^n} = ?$$  I did some computation with big numbers, I guess it is in the interval $\left(\frac{1}{2},1\right)$. "Fake" 3d effect in Photoshop/Illustrator with raster images Will my device work with Ubuntu? I have a device on which I would like to install Ubuntu. How do I find out if Ubuntu will work on it? Reputation displaying incorrectly on Careers (for some accounts) When I go to , go to the "Stack Exchange" section, and click on "edit" under "Accounts", I see the following at the bottom of the account list (partially truncated for reasons of space):    Now, as you can see from my reputation here on MSO, I should have the association bonus on all sites where I have an account. Yet, for some reason, my accounts on Android, Italian, Sound Design, and Windows Phone are listed as having just 1 reputation. However, if you look at my account on each of these sites (, , , and ), you will see that I do, indeed, have 101 reputation from the association bonus.   At first, I thought the commonality among those four sites was that I hadn't performed any actions on them (not even voting), but it turns out that I have actually cast a vote on Android, so I don't really know what's up.   Note also that all of these accounts are at least a few weeks old (and my association bonus is even older than that), so this doesn't seem like it would be a caching issue or anything. Do the Imperials know they are evil? Why is it difficult to differentiate between  and ? Is it because we don't clearly understand how both of these phenomenon takes place?   My thoughts: From an answer to one of my earlier question  I could understand that light waves behave differently when it strikes a slit which is of several times bigger than its wavelength and when it strikes a slit of size comparable to it its wavelength.In the former case the different points on the slit acts as wave-front sources producing circular wave fronts which interfere to form the diffraction pattern but in the later case plane wave-front striking a slit after passing through it forms circular wave-fronts and two such wave-fronts from two different slits interfere to form the interference pattern. But, I'm not satisfied by that because I don't get any intuition about points on the slit acting as wavefront sources. So, what is actually happening? Filter the score of the questions on the homepage before loading them At the moment questions on the homepage are loaded by the top N most recent and then ones with a score of -4 or less are filtered out. This doesn't make much difference for a user who is logged in but consider anonymous users; their home page is only 15 questions in length. If someone was to edit several posts that bump to the top with a score of -4 or less then the home page looks tiny. At the moment on SFF, for example, the homepage for anonymous users only shows 9 questions:  At one point it only showed 3 questions (a few weeks back):  Can the filtering logic be changed to before the questions are loaded to appear on the homepage? Why does the Cauchy distribution have no mean? From the distribution density function we could identify a mean (=0) for Cauchy distribution just like the graph below shows. But why do we say Cauchy distribution has no mean? Process Unicode files with BOM correctly with POSIX tools Trying to use grep today, I ran into the  of the  in a Unicode file (UTF-8, in this case). Specifically, I was trying to find a file beginning with XYZ with the pattern grep '^XYZ', but of course grep treated the BOM as three separate characters and did not match the first line of the file if the first line started with XYZ. I even tried to update the regular expression to ignore spaces ('^[[:space:]]*XYZ'), but to no avail.  Other questions have dealt with  or , but I want to know if POSIX tools have a general option to handle Unicode files correctly. If grep handled the Unicode file correctly, it would consider the file contents to start after the BOM and match XYZ on the first line just like any other line. What goes wrong if we add a mass term for gauge bosons without the Higgs mechanism? How can I get suffix matching in a search in SharePoint 2013? I'm new to SharePoint 2013 and I'm quite puzzled, that it seems to be impossible to search for the middle part of a string.  Simple example:  I've added a lot of documents (PDFs, ...) from our Windows Server to the SharePoint Library and I want to add metadata. I try to filter the view of the document library, to only get those documents which I currently want to edit.  The names of the documents are very systematic, composed of naming conventions with abbreviations like:  Superthing2000-b_Suppl_REF_13580_note_1108_04en which means e. g.: Document about Product "Superthing2000", variant "b", Supplement to the manual, ID "13580", from 08/2011 in english language.  Now, I'd like for example to filter out all documents containing ID 13580 or "en" for english, but no chance, as suffix matching is not possible, even if I explicitly search for e. g. *en*.  Is there a way to define a search with kind of a "contains" operator which also finds files when the search string is only a part in the middle of the file name? Even the Windows Explorer search feature is able to do that!! How to mount read-write an ext4 partition on Windows? How can I connect the top loop to the down loop with faces Hey I want to connect the bottom loop with the top loop so that it forms a solid.  I have tried selecting multiple vertices and pressing F but that just creates a large face which I do not want. I have tried using grid fill bu that doesn't work either. The solution that seems to work is by selecting four vertices and pressing F and then selecting the next 4 and pressing F and on and on. That just takes too long. How to find real world Selenium projects Where can I find sample or real Selenium projects. All the material I can find on github and on internet are basic, and never intermediate or advanced.  How does a real Selenium project look in real life? How can I find sample code?