groupadd: group 'xxxx' already exist I have created a group in Ubuntu terminal called terminal using groupadd terminal command and when I list out the groups using groups command it will not show the newly created group name in the output but if I add the same group again it gives me   groupadd: group 'terminal' already exists   error message but the group name exists in /etc/group file. Why I am not able to see the newly added group while running group command?
How to add existing user to an existing group? I want to add the Apache user (www-data) to the audio group. I've read the man page for useradd, but I'm not having any luck. I'm running xubuntu 11.10. Here's what I'm doing:  $ sudo useradd -G audio www-data useradd: user 'www-data' already exists   If I leave out the -G option, bash, prints the help info for useradd:  $ sudo useradd  audio www-data Usage: useradd [options] LOGIN Options: -b, --base-dir BASE_DIR       base directory for the home directory...   It's not clear to me from the man page what options I should use to make this work.
Best way to get last identity inserted in a table leaflet geojson coordinate problem I just started to play with leflet/geojson a little. But my coordinates are not rendered properly and I have no clue what is going on.  My coordinates are: 52.23943, 4.97599. They work correct with the setView function.  var map = L.map('leaflet_map').setView([52.23943, 4.97599], 15);   But using a geojasonFeature they are, hmmm, 'projected', somewhere east of Somalia.  var geojsonFeature = {             "type": "Feature",             "properties": {             "name": "Coors Field",             "amenity": "Baseball Stadium",             "popupContent": "This is where the Rockies play!"             },             "geometry": {                 "type": "Point",                 "coordinates": [52.23943, 4.97599]             }         };         var myLayer = L.geoJson().addTo(map);         myLayer.addData(geojsonFeature).bindPopup("I am a gjson point.");   Anyone who knows what is happening here?  EDIT  Out of pure curiosity I changed the coordinates around [4.976143930893815,52.23925499011473] and the point appears at its correct location. A known bug!? How to derive variance-covariance matrix of coefficients in linear regression What factors determine enemy levels or: How do enemy levels scale to the player character's? How to install Ubuntu on portable external Hard Drive? OS: Windows 7. I want install Linux Ubuntu on portable external Hard Drive USB 2.0. I read a variety of methods, but I'm confused by contradictory advices and methods. Actually, installing Ubuntu on anything other than clean PC looks much more complicated than installing Windows. I need to have Ubuntu package + Python 2.7 + C compiler installed. My external hard drive is partially filled, I need to keep all files.   Will Ubuntu run entirely on external hardrive, without writing anythinhg to Windows system folders and to registry?  Can anyone post detailed guide how install Ubuntu on external hard drive? How do I get the distinct/unique values in a column in Excel? If I have a column with values, and I want to find out what distinct values are in there (not how many - but the actual distinct values), how can I do that?  In SQL Server I would do something like   SELECT Distinct(MyColumn) FROM MyTable Functions of Independent Random Variables Is the claim that functions of independent random variables are themselves independent, true?   I have seen that result often used implicitly in some proofs, for example in the proof of independence between the sample mean and the sample variance of a normal distribution, but I have not been able to find justification for it. It seems that some authors take it as given but I am not certain that this is always the case. When to use "If I was" vs. "If I were"? Clickable Table Footnote I'm trying to have some clickable footnotes within tables. I tried using \footnote{}, it does create a link but there's no footnote text associated with it. \footnotemark[number] along with \footnotetext[]{} does create a fotenote but then there's no hyperlink. (I would like to make it clear that I'm trying to have footnotes at the bottom of the page and not footnotes within the table.)  Here's a small code snippet:  \documentclass{report}  \usepackage{hyperref} \begin{document}  \begin{table}[h!]     \centering     \begin{tabular}{|r|r|r|}         \hline         A\footnote{Test!} &amp; B\footnotemark[4] &amp; C\footnotemark[5]\\         \hline         123 &amp; Tim &amp; Jane\\         \hline         456 &amp; Tom &amp; Jung\\         \hline     \end{tabular}     \caption{A table} \end{table}  This is a clickable footnote\footnote{You clicked me!}.  \footnotetext[4]{This is B} \footnotetext[5]{This is C}  \end{document} When using unicode-math, how do I get the original calligraphic alphabet back? I am happy with the great majority of what unicode-math does. But at times I find that I prefer a symbol the way it was before. With \varnothing and \complement, for example. In those cases I was able to save them under a different name before loading unicode-math, but this doesn't always work.  Right now I'm trying to access the \mathcal alphabet from plain LaTeX. How might I accomplish this?    Additional Question  I've been looking through unicode-math, trying to figure out where exactly the original \mathcal alphabet gets discarded, but I eventually gave up.  It would be interesting if someone could explain:   how/where the original \mathcal font is defined anyway, and what kind of 'switch' is thrown by unicode-math that makes it unavailable. Cannot login to chat.meta.stackexchange.com; server error when trying to access chat homepage I just recreated my MSE account after having deleted it a few years ago. Now, I'm trying to log in to Meta Stack Exchange Chat, and whenever I try to do so, it just fails silently and I'm still logged out.  Additionally, in the same browser session that I'm supposedly logged out, I get a server error when accessing the chat homepage or the chat profile page of any user. I don't get any errors when trying to access any of these pages in a private session. I also was able to sign in to Stack Exchange Chat and Stack Overflow Chat without problems, since my accounts on SO and my parent site for SE chat haven't been deleted.  I think it might be because it's trying to sign me in to my old chat profile, which was not deleted, but that is associated to my old, deleted site account, which clash and thus cause it to fail. Will having multiple domains improve my seo? In SQL Server, how do I generate a CREATE TABLE statement for a given table? I've spent a good amount of time coming up with solution to this problem, so in the spirit of , I'm posting it here, since I think it might be useful to others.   If anyone has a better script, or anything to add, please post it.  Edit: Yes guys, I know how to do it in Management Studio - but I needed to be able to do it from within another application. infinite monoid H that is not a free monoid and contains a free monoid as a submonoid Let $H= \langle h_1, \ldots , h_n \rangle$ ($n&gt;1$) be an infinite monoid that is not a free monoid. Does $H$ contain an isomorphic copy of a free monoid as a submonoid? EDIT. It is a natural question. The corresponding question for groups is the Burnside problem. When changing fields, should I focus more on describing past research or connecting it to the new area in my statement of purpose? I want to change my field from molecular biophysics to theoretical ecology. While they are basically required some same basic background (physics, math, programming), the rest is quite irrelevant. In my current draft of this part, about a half is about this the problem and the result of the work, another half is for my contribution and what I've learnt. Having said that, should I focus less on describing the work and leave space for the thing that will be useful for the next research?  Below is copy from .     What have you already done? What problems have you solved, or at least worked on? What independent projects have you been part of? What were your key contributions? What did you learn? What did you teach the world? How do your results compare to what was already known? What original ideas are you most proud of? Be specific, technical, credible, and confident (but not arrogant). Refer the reader to your web page for more details. Have a web page with more details: preprints, project reports, source code, videos, etc. How to install Ubuntu on VirtualBox? How to bypass "Verify your account" (Factory Reset Protection) So, if we have a large pipe which is constricted in the middle, the fluid in the middle section  will move faster. Why is it so? What dictates that liquid that an X amount of it must pass on the other side regardless of the size of the encasement?  The only reason I could think about is because that the initial pressure which causes the movement somehow is being transferred to a smaller area, but that makes no sense. Reputation changes not visible in the achievement box (again) Just like , which was marked as . But today, it's not working again. I'm still notified of new badges:      Update: it looks like new events are now updated; reputation events from earlier this UTC afternoon are still missing: What is "angle of view" in photography? I read on the :     Focal-length determines the angle-of-view seen through a lens for a   given sensor-size. With a full-frame sensor a lens gives the same   angle-of-view as it would on a 35mm film camera. With a smaller   sensor, the angle-of-view becomes smaller. The crop-factor, also   called FLM, is the ratio representing the difference in equivalent   focal-lengths. So a 150mm on a full-frame DSLR such as the Nikon D700   gives the same angle-of-view as a 100mm on a D7000 since its FLM is   1.5X.      Short focal-lengths show a greater angle-of-view compared to longer   ones. [...]   In layman's terms, what is angle-of-view? Is it the same as focal length? If not, how is it different? How is it used? Why do I need to know about it?