How to recover files I deleted now by running rm *?
Recovering accidentally deleted files
How to remove session entries from LightDM? Need hint: Determine whether the series $\sum_{n=1}^{\infty}(\frac{n}{n+1})^{n^2}$ is convergent or divergent. Determine whether the series $\sum_{n=1}^{\infty}(\frac{n}{n+1})^{n^2}$ is convergent or divergent.  I've tried applying all the basic tests to no avail. I need to find out what the "trick" for this particular series is. Asymptote: when white isn't white I'm trying to display a white 3D ball with Asymptote (3D PDF), but it always turns up gray:    import graph3; import solids;  defaultrender.merge=true; size(10cm,0);  currentprojection=orthographic(-Z);  //currentlight=Headlamp; //currentlight=light(-10,1,1); //currentlight=White; currentlight=Viewport;  draw(unitsphere,rgb(1,1,1));   I understand it's a lighting issue, and I've tried playing with its settings (the lines commented out in my source are some of my attempts), but I never manage to have white be white. If I understand correctly, I need a whiter diffuse component in my light, but I cannot see how to achieve that. And the documentation is not very clear…    This will be part of a molecular model, and the rendering I'm going for it something like this: What's the fastest way to count the number of keys/properties of an object?  It it possible to do this without iterating over the object?  i.e. without doing  var count = 0; for (k in myobj) if (myobj.hasOwnProperty(k)) count++;   (Firefox did provide a magic __count__ property, but this was removed somewhere around version 4.) At the start of A New Hope, when the corvette is being attacked, C3PO says something to the effect of:     There'll be no escape for the princess this time.   But when Luke stumbles onto Leia's message in R2D2, C3PO seems to not know who the figure in the message is:     I'm afraid I'm not quite sure, sir. I think she was a passenger on our last voyage. A person of some importance, sir - I believe.   Is C3PO feigning ignorance to protect her, or does he really not recognize her? I came to this conclusion: the primes that can't be written as the sum of two squares (lets use$p\prime$ to denote) can be written as ${p}\prime \equiv 3 \;(\bmod\; 4)$.  I need a simple proof to show this and am stuck. I would appreciate guidance! How should I handle questions which are answered in the comments? Sometimes I have asked a question which got no answers, but is answered in the comments to the question.  How should I handle these questions? I can't accept an answer, so it is never an accepted question.  For example this one:   (ok here the answer in the comments is from me, but nevertheless I also have others of them) How to prove the divisibility rule for $3\, $ [casting out threes] The divisibility rule for $3$ is well-known: if you add up the digits of $n$ and the sum is divisible by $3$, then $n$ is divisible by three.  This is quite helpful for determining if really large numbers are multiples of three, because we can recursively apply this rule:  $$1212582439 \rightarrow 37 \rightarrow 10\rightarrow 1 \implies 3\not\mid 1212582439$$ $$124524 \rightarrow 18 \rightarrow 9 \implies 3\mid 124524$$  This works for as many numbers as I've tried.  However, I'm not sure how this may be proven.  Thus, my question is:     Given a positive integer $n$ and that $3\mid\text{(the sum of the digits of $n$)}$, how may we prove that $3\mid n$? Why is the space between words in my source code listing so big? I used the following code to list my java code, but the it looks like there's too much space between words. What can I do?  % source code listing \usepackage{listings} \usepackage{color} \usepackage{xcolor}  \usepackage{caption}  % citation style \usepackage{apacite} \DeclareCaptionFont{white}{\color{white}} \DeclareCaptionFormat{listing}{\colorbox{gray}{\parbox{\textwidth}{#1#2#3}}}  \begin{document} \begin{lstlisting}[label=some-code,caption=bind to service call] bindService(new Intent(this, Recognizer.class), recConnection, Context.BIND_AUTO_CREATE); \end{lstlisting} \end{document}   The snapshot of what I got. The code not completely shown, and space too wide, in function bindService. Asking the position of a person in a sequence mysqldump, preserve update_time and modify_time attributes as listed by show table status from Does mysqldump preserve the create_time and update_time attributes that are output by show table status from?  If not, is there an option that does this?   it looks like mysqldump preserves this data if you export to XML. EDIT: Well the data is included in the export. Whether it's read in at the other end I'm not sure.  Is there a way to do this with a normal .sql dump? For example Lets use the Marrutact from Sandstorm, it can cast as a 5th level wizard. if it then takes a prestige class that requires the ability to cast 1st level Arcane spells and advances arcane casting such as Abjurant Champion. assuming it meets all other prerequisites does the Marrutacts spellcasting improve when it takes a level in Abjurant Champion or does it gain no benefit? Assume that $f(x),g(x)$ are positive and are in $L^1$. Moreover, they are differentiable and their derivative is integrable. Let $h(x)=f(x)*g(x)$, the convolution of $f$ and $g$. Does the derivative of $h(x)$ exist? If yes, how can we prove that $$ \frac{d}{dx}(f(x)*g(x)) = \left(\frac{d}{dx}f(x)\right)*g(x)$$  Thanks Reasons not to use a 741 op-amp? Simple enough question. Why not use a  in a target circuit or anyone's target circuit? What are the reasons not to use it? What might be the reasons to still choose this part? Adobe Illustrator: Lines with stroke < 2.0pt doesn't change color I created lines using the line segment tool in Adobe Illustrator (latest Adobe Cloud version) and I can't change the color of the stroke (through the Appearance panel) if the stroke weight is less than 2.0pt.   If the stroke is 2pt or more, then the color around the line changes but not the line itself.    The whole behavior is odd for me as I've never faced in Illustrator before.  Edit: added screen below with the line selected. With the ls command, is it possible to show only the files created after a specific date, hour...?  I'm asking it because I have a directory with thousand of files.  I want so see all files that were created since yesterday.   I use ls -ltr but I have to wait to see all files...  There is an equivalent of DIRECTORY/SINCE=date from OpenVMS ? I want to copy any file to my external hard drive. But always when I tried to do this I have next output:  cp: cannot create regular file /media/NameOfCard/[file]' : Read only file system  I also tried:  sudo chmod -R 775 /media/NameOfCard sudo chmod -R 777 /media/NameOfCard   But the same effect - ... Read only file system  Update:   After mount I have next output:  nazar_art@nazar-desctop:~$ mount /dev/sda1 on / type ext4 (rw,errors=remount-ro) proc on /proc type proc (rw,noexec,nosuid,nodev) sysfs on /sys type sysfs (rw,noexec,nosuid,nodev) none on /sys/fs/fuse/connections type fusectl (rw) none on /sys/kernel/debug type debugfs (rw) none on /sys/kernel/security type securityfs (rw) udev on /dev type devtmpfs (rw,mode=0755) devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620) tmpfs on /run type tmpfs (rw,noexec,nosuid,size=10%,mode=0755) none on /run/lock type tmpfs (rw,noexec,nosuid,nodev,size=5242880) none on /run/shm type tmpfs (rw,nosuid,nodev) /dev/sdb1 on /media/sdb1 type vfat (rw) binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,noexec,nosuid,nodev) gvfs-fuse-daemon on /home/nazar_art/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,user=nazar_art)   Any suggestions?   How to solve this trouble and let permission to copy and delete files to hard drive? Get bytes from std::string in C++ I'm working in a C++ unmanaged project.  I need to know how can I take a string like this "some data to encrypt" and get a byte[] array which I'm gonna use as the source for Encrypt.  In C# I do    for (int i = 0; i &lt; text.Length; i++)     buffer[i] = (byte)text[i];   What I need to know is how to do the same but using unmanaged C++.  Thanks! What do you call a person who keeps talking about art; studies art, criticizes art, and thinks he'd be amazing with it. But he doesn't practice it Seeking Symbology for Interactive Mapping? When a user clicks on a map what should they expect to see?   I would say a symbol for where they clicked.  A pushpin seems to be the most accepted icon for generic data. Google has pushed the upside down tear drop.   What are other ideas/options and is there a place for finding professional gis oriented icon packs?  I ended up creating this,     This just popped up from the guys at map box. Clean