I'm trying to create a function that will echo the previous to last command from the current terminal. This is the expected output (here I call the desired function f):  $ history 1 history 1 $ f history 1     Side question: Where does history(1) saves the current terminal's history. I know that when the terminal session ends history is typically saved in $HISTFILE (which is set to ~/.bash_history in my case). But I'd like to know where history(1) keeps the history of the currently running terminal.
If I run history, I can see my latest executed commands.  But if I do tail -f $HISTFILE or tail -f ~/.bash_history, they do not get listed.  Does the file get locked, is there a temporary location or something similar?
Why didn't Snape keep or secure his copy of Advanced Potion-Making? 0 ram free on ICS How to pack a sphere with cubes? I read a little bit about , but I imagine the problem changes drastically when trying to fill a sphere with unit cubes. For example, how many unit cubes could one fit into a sphere of radius five? Clearly the upper limit would be $\left \lfloor \frac{4}{3}\pi \cdot 5^3 \right \rfloor$, but I imagine there will be plenty more empty space than just a small fraction of a cube. I want to show that for $S,T\in B(H)$ bounded operators on Hilbertspace with $S\geq 0,T\geq 0$ and $ST=TS$,  we have $S+T\geq 0$, and $ST\geq 0$.  $T\geq 0$ means $(Tx,x)\geq 0$.    To me it seems that $((S+T)x,x) = (Sx,x)+(Tx,x)\geq 0$. But for $ST$ i like some help.   There is a theorem in Rudin (12.32) that says that for every $T\in B(H)$ we have an equivalence:   $T$ is positive $\Leftrightarrow$ $T$ is self adjoint, i.e. $T=T^*$ and $\sigma(T)\subset [0,\infty)$.   Since $S, T$ are self adjoint we know that $ST=TS = S^*T^* = T^*S^*$ ($ST$ is selfadjoint since $S,T$ commute). Also I read somewhere that if $S,T $ commute then $\sigma(ST)\subset \sigma(S)\sigma(T)$, but I am not sure if this is true. Clearly I cant prove it, but if it were true by this ''Theorem'' it would follow that $ST \geq 0$.   Is there a more straightforward way? As a(n) noun vs as only how to reset a lost admin password? Overstaying on a US Visa Waiver Program A friend of mine came from Australia on the WVP and stayed 92 days. I made a mistake booking Her flight scheduling a Saturday arrival/departure at DFW. This amounted to a 92 day stay and with no funds to rebook a low cost flight through Qantas it was necessary to leave on the scheduled flight.   Question # 1) Was a automatic I-94W submitted by the airlines? She had no customs forms to fill out upon departure.   Question #2) How does this effect another WVP being issued if applied for? Can I run my CPU at 100% usage for a long time? I have a Dell XPS 15 9570, 32 GB ram, 2.2 ghz and 6 cores. When i use an application (The parsim command on MATLAB) ()  then my fan starts running fast , during this my PC doesn't seem to be heating but it never got this noisy in the past so it got me worried. In my task manager , the CPU usage shows 100% when this application is running.   Is it a problem for the life of laptop, if I run the PC at CPU 100% for like 4 hours in a day? Do I need to be worried about the noisy fan during the application? Sums in math mode: how to display index under the sigma sign? I have a fraction with sums above and under the line. How can I convince LaTeX to write the indices of the sums under the sigma instead of next to it?  \begin{displaymath}   \frac{\sum_{s \in S} s^2}{\sum_{p \in P} p^2} \end{displaymath} Is there some rare language construct I haven't encountered (like the few I've learned recently, some on Stack Overflow) in C# to get a value representing the current iteration of a foreach loop?  For instance, I currently do something like this depending on the circumstances:  int i = 0; foreach (Object o in collection) {     // ...     i++; } Self-Contained Proof that $\sum\limits_{n=1}^{\infty} \frac1{n^p}$ Converges for $p > 1$ I use multiple displays, and the available options for Spaces that I am aware of allow surprise Space-switching, even when working in a completely different space.  Ideally, interacting with the Dock will only affect the same Space on the same display on which I used the Dock. This means:   If app clicked in Dock, and no copy of app is running on any space, then start the app and confine it to the current Space. If app clicked in Dock, and the program is already running in another Space, then either 1) open a new window if the program allows this, or 2) silently move the app to the current Space without disturbing or changing any other Space or display. If app clicked in Dock, and the program is already running in the current Space, then change focus to the app.   Specifically: - Clicking an icon in the Dock should rarely affect any other Space. - Clicking an icon in the Dock must never affect which Space is displayed on which display  OS X Yosemite 10.10.2, MacBook Pro 2012. (Dock set to auto-hide, and pops up at the bottom of any screen when I put the mouse there.) Can one create a video from sequence of meshes that you already have using blender? If I have a sequence of .obj (or any other readable format) files created from my own simulation code (say cloth simulation), can I use the rendering capabilities of blender to generate a video?   Is there a way to set the material properties for frame 1 and use the same or rest of the frames while the corresponding meshes are imported afresh from that ones I provide? What is the relation between electromagnetic wave and photon? I find that the minimum in-call volume on my HTC Desire is still far to loud on some calls.  Since I got the phone, I have flashed several different custom ROMs, radio updates, etc, and have had the issue throughout.  Do you know of any way (setting, hack, app, whatever) to reduce the minimum volume?  My device is rooted and I am currently running one of the CyanogenMod 7 (Gingerbread) nightly builds. It says that Cognito Forms can send email notifications when a form is submitted. Where would I find those email notification settings?   I would like for my website clients to be the recipients of those email notifications. Do they have to have an account or a verified email address?   Also, is the form data included in the email notification? Also, is there an advantage to using the WordPress Plugin vs the regular embed code? Use a .jar java library API in C#? I'm an entry level programmer so please be descriptive in your responses.  I am trying to use a Java API given as a .jar file in my C# .net application.  I don't know much Java, but this .jar file says "no main-class manifest attribute" when I try to run it so this means its a library?  This Java API also comes with a .java file which shows how to use the library but I cannot see the code inside the .jar.  I found  on this site, and one of the answers reads, "In simple way you can pack your java classes to jar file then In C# use Process class for execute and map IO stream."  I am semi-familiar with the Process class in C# but I don't understand how I could use it to use a Java library in my C# .net project.  Is this possible? or was that answer incorrect?  If so, could you explain how I can use the .jar library in my C# app. I'm having exactly the same issue as , also using Biber 2.14, albeit I didn't upgrade, downgrade, change TexLive version, change encoding or (seemingly) do anything. It's like Biber suddenly quit parsing dates on me.  Whether the bibfile is encoded in ASCII or UTF-8 makes no difference. Whether the date is a short format or the full YYYY-MM-DD makes no difference. I'm not sure what else to test.  Here's a MWE and the associated .blg file:  \begin{filecontents}{mwe.bib}     @Article{JD2020,         author       = {John Doe},         title        = {A Title},         date         = {2020-01-01},         %date       = {2020}         journaltitle = {Journal},     } \end{filecontents}  \documentclass{article} \usepackage{biblatex} \addbibresource{mwe.bib}  \begin{document}     test\autocite{JD2020}     \printbibliography \end{document}   [1] Config.pm:304&gt; INFO - This is Biber 2.14 [1] Config.pm:307&gt; INFO - Logfile is 'mwe.blg' [154] biber-darwin:322&gt; INFO - === Thu Apr 30, 2020, 11:04:33 [185] Biber.pm:415&gt; INFO - Reading 'mwe.bcf' [354] Biber.pm:943&gt; INFO - Found 1 citekeys in bib section 0 [384] Biber.pm:4256&gt; INFO - Processing section 0 [385] Utils.pm:75&gt; INFO - Globbing data source 'mwe.bib' [385] Utils.pm:91&gt; INFO - Globbed data source 'mwe.bib' to mwe.bib [401] Biber.pm:4455&gt; INFO - Looking for bibtex format file 'mwe.bib' for section 0 [402] bibtex.pm:1653&gt; INFO - LaTeX decoding ... [406] bibtex.pm:1471&gt; INFO - Found BibTeX data source 'mwe.bib' [437] Utils.pm:304&gt; WARN - Entry 'JD2020' (mwe.bib): Invalid format '2020-01-01' of date field 'date' - ignoring [457] UCollate.pm:68&gt; INFO - Overriding locale 'en-US' defaults 'normalization = NFD' with 'normalization = prenormalized' [457] UCollate.pm:68&gt; INFO - Overriding locale 'en-US' defaults 'variable = shifted' with 'variable = non-ignorable' [457] Biber.pm:4084&gt; INFO - Sorting list 'nty/global//global/global' of type 'entry' with template 'nty' and locale 'en-US' [457] Biber.pm:4090&gt; INFO - No sort tailoring available for locale 'en-US' [461] bbl.pm:652&gt; INFO - Writing 'mwe.bbl' with encoding 'UTF-8' [463] bbl.pm:755&gt; INFO - Output to mwe.bbl [463] Biber.pm:128&gt; INFO - WARNINGS: 1   The \printbibliography output actually looks like this: [1] John Doe. “A Title”. In: Journal ().  In my actual thesis, all the dates are gone from the pdf output. C++ map access discards qualifiers (const) The following code says that passing the map as const into the operator[] method discards qualifiers: #include &lt;iostream&gt; #include &lt;map&gt; #include &lt;string&gt;  using namespace std;  class MapWrapper { public:     const int &amp;get_value(const int &amp;key) const {         return _map[key];     }  private:     map&lt;int, int&gt; _map; };  int main() {     MapWrapper mw;     cout &lt;&lt; mw.get_value(42) &lt;&lt; endl;     return 0; }  Is this because of the possible allocation that occurs on the map access? Can no functions with map accesses be declared const? MapWrapper.cpp:10: error: passing const std::map&lt;int, int, std::less&lt;int&gt;, std::allocator&lt;std::pair&lt;const int, int&gt; &gt; &gt; as this argument of  _Tp&amp; std::map&lt;_Key, _Tp, _Compare, _Alloc&gt;::operator[](const _Key&amp;)  [with _Key = int, _Tp = int, _Compare = std::less&lt;int&gt;,  _Alloc = std::allocator&lt;std::pair&lt;const int, int&gt; &gt;] discards qualifiers Is there a word for when an action has an effect opposite to the one intended? Is there a word or phrase to express the concept of an action having the opposite effect of the expected outcome?  For example, a drug taken to cure headaches that actually causes headaches, or an advertising campaign designed to deter smoking that leads to an increase in smoking.