What's really the difference between:  env VARIABLE=VALUE command   and   VARIABLE=VALUE command   in bash-compatible shells?   Note: I've done some testing myself and I couldn't see any difference  Edit: An example would be  EDITOR=nano visudo   vs  env EDITOR=nano visudo
What is the difference between the command  $ env FOO=bar baz   and  $ FOO=bar baz   What effect does env have?
I use babelbib and I have a source with two authors. Contrarily to when using the plain bib style, as soon as I switch to babplain, the author names are formatted like this:  [1] Müller, Jan und Eva Schulze: Name of the book, 2015.   While I would like both author names to be formatted the same way, that is one of these:  [1] Müller, Jan und Schulze, Eva: Name of the book, 2015. [1] Jan Müller und Eva Schulze: Name of the book, 2015.   sources:  % test.tex \usepackage[ngerman]{babel} \usepackage[fixlanguage]{babelbib} \selectbiblanguage{ngerman} \bibliographystyle{babplain} \bibliography{test}  % test.bib @manual{foo,     author = "Müller, Jan and Schulze, Eva",     title = "Name of the book",     year = "2015", }   I can fix it by specifying and {Schulze, Eva}, but that way all is treated as the last name, that cannot be the solution, can it? Oneboxing is a handy feature in chat for quickly previewing links, but the list of supported sites is very small, and occasionally boxes for sites such as Wikipedia can break and fetch any image/text.  Instead of having to request additional sites to be added to the onebox list (, , , , , and of course ), we could let the sites themselves handle the oneboxing with some &lt;meta&gt; tags, such as:  &lt;meta name="onebox-title" content="The Onebox Title"/&gt; &lt;meta name="onebox-image" content="/image.png"/&gt; &lt;meta name="onebox-summary" content="This is the summary for a site's onebox"/&gt;   Then when a link is placed on its own in chat, the oneboxing spider would look for these tags and, if they are found, show the appropriate data.  Support for these tags would certainly be bad (for lack of any real better term) at first, though most users of SO chat could easily add it to their personal / company's sites (should they be in such a position) and writing friendly suggestions to other sites to implement them isn't exactly a gargantuan effort.  This would also present an opportunity for currently oneboxed sites to set in stone what should be shown, such as each Wikipedia article setting the main image to be oneboxed instead of SO's spider picking one willy-nilly.  Finally, sites implementing these tags would lay the foundation for other sites and services to develop similar features to the onebox, without having to write per-site scrapers. How to use "tens of" and "hundreds of"? If I'm not mistaken, tens of means 10 to 99 and hundreds of means 100 to 999. Is this correct? I found in some dictionaries that tens of is actually not correct.  I also found that hundreds of could also mean any arbitrary large number. So how would people usually interpret hundreds of? Based on context?  In my case, I want to describe numbers of some items that are usually 50-90 but sometimes could be around 100-200, but definitely not as many as 300 or so. I want to really emphasize that there are a lot of these items. In this case, can I say "... have tens or even hundreds of ..."? Would people misinterpret what I actually want to say? Who decides which half of the universe should be destroyed? Although my question is based on the comic mini-series Infinity Gauntlet issues #1 through 6, I'm open to any and all answers (i.e Movies, other comic books etc. etc.) across the Marvel multi-verse.   It was elegantly presented in the Infinity Gauntlet series how Thanos, after collecting all the soul gems snaps his fingers and destroys half the universe.  Additionally, in the recent movie Avengers: Infinity War,       Thanos does it again! He snaps his fingers and destroys half the universe.   However, one thing is unclear to me. In both cases,      Half the universe is destroyed (or obliterated, or erased from existence).   But who decides which half of the universe should not exist anymore? Does the wielder of the Gauntlet choose, or is the Gauntlet (along with the stones) sentient enough to make the decision? How can I verify a Google authentication API access token? How can I verify a Google authentication access token?  I need to somehow query Google and ask: Is [given access token] valid for the [example@example.com] Google account?  Short version: It's clear how an access token supplied through the  can be used to then request data from a range of Google services. It is not clear how to check if a given access token is valid for a given Google account. I'd like to know how.  Long version: I'm developing an API that uses token-based authentication. A token will be returned upon provision of a valid username+password or upon provision of a third-party token from any one of N verifiable services.  One of the third-party services will be Google, allowing a user to authenticate against my service using their Google account. This will later be extended to include Yahoo accounts, trusted OpenID providers and so on.  Schematic example of Google-based access:    The 'API' entity is under my full control. The 'public interface' entity is any web- or desktop-based app. Some public interfaces are under my control, others will not be and others still I may never even know about.  Therefore I cannot trust the token supplied to the API in step 3. This will be supplied along with the corresponding Google account email address.  I need to somehow query Google and ask: Is this access token valid for example@example.com?  In this case, example@example.com is the Google account unique identifier - the email address someone uses to log in to their Google account. This cannot be assumed to be a Gmail address - someone can have a Google account without having a Gmail account.  The Google documentation clearly states how, with an access token, data can be retrieved from a number of Google services. Nothing seems to state how you can check if a given access token is valid in the first place.  Update The token is valid for N Google services. I can't try a token against a Google service as means of verifying it as I won't know which subset of all Google's services a given user actually uses.  Furthermore, I'll never be using the Google authentication access token to access any Google services, merely as a means of verifying a supposed Google user actually is who they say they are. If there is another way of doing this I'm happy to try. I appreciate the mechanisms which help bring attention to new answers to old questions - front page sorting, and the moderation tool explicitly designed for it. But I wonder if we can do more. I'm particularly interested in addressing answers whose validity has changed. In the worst case, they were correct when they were posted, but no longer are, so they mislead all the current users who find their way to them looking for an answer. More benignly, perhaps the best answer was good, but slightly flawed.  At this point, a helpful user may post a new answer, which is much better than existing upvoted and accepted answers. It can be difficult to overcome that momentum. What if the default sorting method took this into account? A naive suggestion: if a new answer has a large positive vote velocity, and an old answer has a negative vote velocity, perhaps the default sorting should place the new answer above the old answer. This could help make new answers visible to users who need a correct answer, and also help garner more votes to increase the confidence of the sorting decision.  I know this would be a fairly low-impact change, but nothing is permanent, and I'm afraid of answers with 100 upvotes being pinned at the top for years after they've become obsolete.  Edit: I would welcome other proposals that accomplish the same goal - my naive suggestion wasn't intended to be a complete solution, just one thing that a better sorting method would do. POSTFIX main.cf permission denied What are the differences between a bridge camera and a DSLR? What  are the differences between a bridge camera and a DSLR? Brand new disk brakes are barely stopping the bike How to sanity check a date in Java I find it curious that the most obvious way to create Date objects in Java has been deprecated and appears to have been "substituted" with a not so obvious to use lenient calendar.  How do you check that a date, given as a combination of day, month, and year, is a valid date?  For instance, 2008-02-31 (as in yyyy-mm-dd) would be an invalid date. Contracting with Levi-Civita (totally antisymmetric) tensor Show that a number has a terminating decimal expansion if and only if, it is rational and when in lowest terms, its denominator is coprime to all primes other than $2$ and $5$.   This is an unsolved question in my lecture notes. I can only seem to prove the converse direction for this. Would appreciate a solution for the other direction.     For converse direction:   Let the number, in lowest terms, be given by $\frac{l}{m}$ where $m = 2^ \alpha 5^\beta$, for some positive integers, $\alpha$ and $\beta$.    If $\alpha &gt; \beta$, let $k = 5^{(\alpha-\beta)}$. If $\alpha &lt; \beta$, let $k = 2^{(\beta-\alpha)}$.   Then $\frac{l}{m} = \frac{kl}{k2^\alpha5^\beta}=\frac{kl}{10^q}$ where $q = \max(\alpha,\beta)$.   Hence $\frac{l}{m}$ is a terminating decimal. Proving $\sum_{k=0}^n(-1)^k\binom nk=0$ Show that $$\sum_{k=0}^n(-1)^k\binom nk=0$$ So for odd $n$ we have an even number of terms. So $\binom nk=\binom n{n-k}$ which have opposite signs. Thus the sum is 0.  For even $n$ we have that $$\sum_{k=0}^n(-1)^k\binom nk= \binom n0+\sum_{k=1}^{n-1}(-1)^k\binom nk+\binom nn$$ Now $$\sum_{k=1}^{n-1}(-1)^k\binom nk= \sum_{k=1}^{n-1}(-1)^k\left[\binom{n-1}k+\binom{n-1}{k-1}\right]$$ What would that sum be in the square brackets? I'm having trouble with \includegraphics I'm using MacTeX I'm taking a course on waves and oscillations using Crawford from the Berkeley series (out of print excluding international copies), and would like to know if anyone has any suggestions for a better book. We cover:    coupled oscillators, forced oscillators,  Fourier analysis,  traveling waves,    and some other topics. Any help with the topic would be appreciated. "Nikki's and Alice's X" vs. "Nikki and Alice's X" Preposition 'to' with gerund (-ing)? Check this sentence from  (US Department of Education)     Technology ushers in fundamental structural changes that can be integral to achieving significant improvements in productivity.   Cannot it be better as...     Technology ushers in fundamental structural changes that can be integral to achieve significant improvements in productivity.   The preposition to takes gerund (-ing) here. Any rule? .       The  has no sign of the user sharth The  also does not have any sign of related activity   I would like to know why the user's name is associated with the question. At least why their display name shows up as having modified the question timeline activity.  Possible reason that I can think of is that, .  Is this the reason?  Is there a way (for normal users), to look for such details, other than looking at the user activity and the question's revision history. Ubuntu not detecting second monitor I'm running Ubuntu 12.04 on a Lenovo x61s Thinkpad. As the screen's rather small and I want to do some video editing, I thought I'd plug in a monitor and use that. The monitor is Relisys JM777 (quite old).  When I plug it into my other computer, which is running Windows 7, it immediately mirrors the display; but when plugged into the Lenovo the monitor screen remains blank. The graphics card on the Lenovo is a "VGA compatible controller" according to SysInfo.   Anybody got any suggestions for getting this monitor to work? I'm quite new to Linux. In , one learns two definitions of free groups associating with sets.        Let $A$ be a set, the free group of $A$, $F(A)$ is the initial object in the category $\mathcal{C}$, where \begin{equation} \operatorname{Obj}(\mathcal{C})=\{A\xrightarrow{g}G\}, \end{equation}where the codomain $G$ are groups, and \begin{equation} \operatorname{Hom}(\mathcal{C})=\{\text{Commutative Diagrams } A\xrightarrow{g_1}G_1\xrightarrow{\phi}G_2\xleftarrow{g_2}A\}  \end{equation} where $\phi$ are group homomorphisms.   Also $F(A)$ has the concrete construction with elements being non-redundant words with alphabet $A$, and the group multiplication being juxtaposition and reduction.      But what good are free groups? Why are they useful?  says they are useful in topology, but does not explain why explicity.   Can someone give some examples that an undergraduate can understand? I am asking about examples that can show the usefulness of this abstract construction. So I guess the identification of $\mathbb{Z}=F({a})$ does not really count.