Where should we ask questions tightly coupled with software but aren't debugging related?
Which computer science / programming Stack Exchange sites do I post on?
How do I add a launcher for .sh applications? I have installed ubuntu (11.04).  I installed phpstorm which is simply an archive for you to extract and shove in your /opt directory.  To run it you would use /opt/PhpStorm-103.243/bin/PhpStorm.sh  In unity I had created a launcher on my desktop.  Now I have installed gnome-3(gnome-shell),  And I have nothing in my desktop.  So how do I run phpstorm quickly? Can I get it to show up in "applications"? What does "preceding" mean in Oracle? Was Quirrell the Defense against the Dark Arts teacher for more than one year? It's well seen throughout the series that there is a “curse” on the DADA teacher position, that no one can hold that post for more than a year. But it seems like Quirrell has been around for longer than a year. What's up with that? Is "has or will read" grammatical? I just wrote  in an ELL chat room. But looking at it (or more accurately, listening to my "inner voice" trying to "read it aloud"), I find it bothers me a lot.  A quick check on Google Books finds a claimed 432 written instances of , and 910 instances of , which suggests a significant minority of writers don't have a problem with the fact that the two different read's don't sound the same.  When I check the same construction with other verbs that don't have the same written form for past participle and present tense, it seems people nearly always include both (e.g. :1230, :8; :357, :7).  I'm not usually a big fan of "grammatical rules", but it seems to me there "ought" to be a rule that you shouldn't delete one instance of the verb unless it's "the same" as the one you're keeping. And it also seems to me that since language is primarily spoken, "the same" ought to mean "sounds the same when spoken", not "looks the same when written".  Can anyone who knows more than me about formal rules of grammar settle this one?    As an aside, offhand I can't think of any verb where the past participle and present tense sound the same but are written differently (maybe there aren't any), but would deletion be okay in that case? Run TTY script every time I open a GUI terminal Is the set of real matrices diagonalizable in $\mathcal M_n(C)$ dense in the set of all companion matrices? Derivation of binomial coefficient in binomial theorem. How was the binomial coefficient of the binomial theorem derived?  $$\frac{n!}{k!(n-k)!}$$ Exactly half of the elements of $\mathcal{P}(A)$ are odd-sized Let $A$ be a non-empty set and $n$ be the number of elements in $A$, i.e. $n:=|A|$.  I know that the number of elements of the power set of $A$ is $2^n$, i.e.  $|\mathcal{P}(A)|=2^n$.  I came across the fact that exactly half of the elements of $\mathcal{P}(A)$ contain an odd number of elements, and half of them an even number of elements.  Can someone prove this? Or hint at a proof? What are the different ways that a message can be displayed to a bash shell after a user logs in? Why shift-cmd-n fails as a custom shortcut for Firefox "New Private Window"? I created the shiftcommandn shortcut for Firefox in Syst Prefs to match other browsers' behavior.     It registers in the Firefox Menubar.     But pressing the shortcut opens a new non-private window, and it loads there the first item in my "Top Sites".   I imagine I could create another shortcut to override this behavior, but what is this behavior? I don't see anything highlighted in the Firefox Menubar when I hit the shortcut. Or might there be another solution (other than using a different shortcut to open new private windows)?   Problem exists on both Mojave and High Sierra. Default Firefox shortcut (shiftcommandp) still opens a new private window. Allow moderators to edit/delete comments directly from the per-user comment moderation page A while back, a new dashboard was added to the user moderation tools to .  It's great for scouring a user's comment history to find certain comments, but I can't do anything from this dashboard except filter by flagged1, deleted, or active comments, and visit the posts to which the comments are attached where I can then edit or delete them.  Can we have the ability to edit and delete comments from this dashboard just as we're able to from the flag queue? It gets particularly tedious to have to open 100 tabs just to delete 100 spam comments from the posts they're attached to (and no, I'm not making that number up2...).    1 .  2 Alright, fine, I made that up; the actual number of spam comments I had to delete was 111. What exactly is a distribution? I know very little of Probability and Statistics, and am wishing to learn.  I see the word "distribution" used all over the place in different contexts.  For example, a discrete random variable has a "probability distribution."  I know what this is. A continuous random variable has a probability density function, then for $x\in\mathbb{R}$, the integral from $-\infty$ to $x$ of the probability density function is the cumulative distribution function evaluated at $x$.   And apparently just "distribution function" is synonymous with "cumulative distribution function," at least when talking about continuous random variables (question: are they always synonyms?).  Then there are many famous distributions.  $\Gamma$ distribution $\chi^2$ distribution, etc.  But what exactly is a $\Gamma$ distribution?  Is it the cumulative distribution function of a $\Gamma$ random variable?  Or the probability density function of a $\Gamma$ random variable?  But then a frequency distribution of a finite data set appears to be a histogram.  Long story short: in Probability and Statistics, what is the definition of the word "distribution"?    I know the definition of distribution in Mathematics (an element of the dual space of the collection of test functions equipped with the inductive limit topology), but not Probability and Statistics. Ubuntu 20.04 brightness adjust not working I am unable to adjust brightness levels through Gnome. I had the same issue with 18.04 but it was resolved there (honestly, I can't remember how).  lspci|grep VGA 00:02.0 VGA compatible controller: Intel Corporation Core Processor Integrated Graphics Controller (rev 18)  xrandr --output LVDS-1 --brightness 0.95 &lt;-- this works through the terminal excerpt from /etc/default/grub GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"   Thank you in advance. It is my understanding that metals are a crystal lattice of ions, held together by delocalized electrons, which move freely through the lattice (and conduct electricity, heat, etc.).   If two pieces of the same metal are touched together, why don't they bond?   It seems to me the delocalized electrons would move from one metal to the other, and extend the bond, holding the two pieces together. If the electrons don't move freely from one piece to the other, why would this not happen when a current is applied (through the two pieces)? Ubuntu server shows me that I  use allmost all disk:  Usage of /:   95.5% of 118.12GB   And I try to find big folders and files, run ncdu:  ncdu 1.8 ~ Use the arrow keys to navigate, press ? for help                                                                                                                                                  --- / ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------     5.5GiB [##########] /root                                                                                                                                                                                    2.3GiB [####      ] /var   628.6MiB [#         ] /usr   209.9MiB [          ] /lib    28.2MiB [          ] /boot     8.6MiB [          ] /bin     7.7MiB [          ] /sbin     6.6MiB [          ] /etc   208.0KiB [          ] /run   112.0KiB [          ] /tmp    48.0KiB [          ] /opt e  16.0KiB [          ] /lost+found     8.0KiB [          ] /dev     8.0KiB [          ] /media     4.0KiB [          ] /lib64 e   4.0KiB [          ] /srv e   4.0KiB [          ] /selinux e   4.0KiB [          ] /mnt e   4.0KiB [          ] /home     0.0  B [          ] /proc     0.0  B [          ] /sys @   0.0  B [          ]  initrd.img @   0.0  B [          ]  vmlinuz   According to ncdu I use about 10 GiB of 128 GiB - it is about 10 %. Contradiction.  How to clean my ubutntu server without rebooting?  I thought that ncdu lies and used another apps to find big files and folders. All of them shows the same result as ncdu.  And df -h command shows that disk is full.  # df -h Filesystem      Size  Used Avail Use% Mounted on /dev/xvda       119G  113G     0 100% / udev            2.0G  8.0K  2.0G   1% /dev tmpfs           788M  212K  788M   1% /run none            5.0M     0  5.0M   0% /run/lock none            2.0G     0  2.0G   0% /run/shm   Update  sudo du -sch /* result:  /# sudo du -sch /* 8.7M    /bin 29M /boot 8.0K    /dev 6.6M    /etc 4.0K    /home 0   /initrd.img 210M    /lib 4.0K    /lib64 16K /lost+found 8.0K    /media 4.0K    /mnt 48K /opt du: cannot access `/proc/4470/task/4470/fd/4': No such file or directory du: cannot access `/proc/4470/task/4470/fdinfo/4': No such file or directory du: cannot access `/proc/4470/fd/4': No such file or directory du: cannot access `/proc/4470/fdinfo/4': No such file or directory 0   /proc 5.0G    /root 212K    /run 7.8M    /sbin 4.0K    /selinux 4.0K    /srv 0   /sys 112K    /tmp 629M    /usr 2.3G    /var 0   /vmlinuz 8.1G    total   8.1G  total as usual. But I see cannot access rows, maybe problem because of them.  Then I checked the biggest folder in /. It is /root :  /# sudo du -sch /root/* 96K /root/Downloads 2.5G    /root/Dropbox 36K /root/nohup.out 4.0K    /root/npm-debug.log 4.0K    /root/readonly 980K    /root/redis-2.6.16.tar.gz 228M    /root/tmp 2.7G    total How can I generate irregular grid containing minimum n points? Given a large (~ 1 million) sample of unevenly distributed points - is it possible to generate irregular grid (in size, but could also be irregular in shape if that is possible?) that will contain specified minimum amount of n points?   It is of less importance for me if genereted 'cells' of such grid contain exactly n number of points or at least n points.  I'm aware of solutions like  in ArcGIS or  in QGIS/mmgis however they will all create regular grids which will result in an output with empty cells (smaller problem - I could simply discard them) or cells with count of points less than n (bigger problem since I'd need a solution to aggregate those cells, probably using some tools from ?).  I've been googling around to no avail and am open to both commercial (ArcGIS &amp; extensions) or free (Python, PostGIS, R) solutions. Number of connected components of the complement of a compact Let $X$ be a connected, locally compact space and let $K$ be a compact subset of $X$. Is the number of connected components of the complement $X\setminus K$ finite? If it is not, are there some hypotheses over $X$ for finiteness of connected components? Complex number isomorphic to certain $2\times 2$ matrices? I have been trying to prove this, but I am having trouble understanding how to prove the following mapping I found is injective and surjective. Just as a side note, I am trying to show the complex ring is isomorphic to special $2\times2$ matrices in regard to matrix multiplication and addition. Showing these hold is simple enough.  $$\phi:a+bi \rightarrow \begin{pmatrix} a &amp; -b \\ b &amp; a \end{pmatrix}$$  This is what I have so far:  Injective: I am also confused over the fact that there are two operations, and in turn two neutral elements (1 and 0). Showing that the kernel is trivial is usually the way I go about proving whether a mapping is injective, but I just can't grasp this.  $$ \phi(z_1) = \phi(z_2) \implies \phi(z_1)\phi(z_2)^{-1} = I = \phi(z_1)\phi(z_2^{-1}) = \phi(z_2)\phi(z_2^{-1}).$$  So if we can just show that the kernel of $\phi$ is trivial, then it also shows that $z_1 = z_2$. The only complex number that maps to the identity matrix is one where $a = 1$ and $b = 0$, $a + bi = 1 + 0i = 1$.  Using a similar argument for addition we can just say that the only complex number $z$ such that $\phi(z) = 0\text{-matrix}$, is one where $a=0$ and $b=0$, $a+bi=0+0i=0$.   Surjective:  I forgot to add this before I posted, but I honestly don't really understand how to prove this because it just seems so obvious. All possible $2\times2$ matrices of that form have a complex representation because the complex number can always be identified by its real parts and since the elements of the $2\times2$ matrix are real then the mapping is obviously onto.  I have always had trouble understanding when I can say that I have "rigorously" proved something, so any help would be appreciated! Remove pseudo nodes in QGIS Presentation $\langle x,y,z\mid xyx^{-1}y^{-2},yzy^{-1}z^{-2},zxz^{-1}x^{-2}\rangle$ of group equal to trivial group Problem: Show that the group given by the presentation $$\langle x,y,z  \mid xyx^{-1}y^{-2}\, , \, yzy^{-1}z^{-2}\, , \, zxz^{-1}x^{-2} \rangle $$ is equivalent to the trivial group.   I have tried all sorts of manners to try to show that the relations given by the presentation above imply that $x=y=z=e$. However, I am stuck and would appreciate any hints as to how I should move forward.