How to write a matrix like this
How to create the matrix attached that has 2x2 blocks in its diagonal and a square outlining them?
How to debug JavaScript / jQuery event bindings with Firebug or similar tools? how to output text to both screen and file inside a shell script? Currently I have a shell script which logs messages to a log file like this:  log_file="/some/dir/log_file.log" echo "some text" &gt;&gt; $log_file do_some_command echo "more text" &gt;&gt; $log_file do_other_command   When executing this script, there is no output to screen, and, since I'm connecting to the server via putty, I have to open another connection and do "tail -f log_file_path.log", because I can't terminate the running script and I want to see the output in real time.  Obviously, what I want is that the text messages are printed on screen and into file, but I'd like to do it in one line, not two lines, one of which has no redirection to file.  How to achieve this? Identification of mid-80s time travel tv show The blackboard bold font in the AMSFonts package only has capital letters.  I sometimes wish to use a blackboard bold "1", for which I can use \usepackage{bbold}. But this changes the entire blackboard bold font, and I like the original AMSFonts versions of the capital letters better.  Is there a simple way for me to get \mathbb{1} from one package and the blackboard bold capitals from another? Today I started having the following issues in Pokémon GO:   I can't spin pokéStops and get rewards When I catch pokémon, even the lowest CP ones, they escape every time. I've tried using razz berries, that doesn't work. Neither does using great balls.   I do have Internet. I'm not on wifi. I can send messages and browse Internet.  NOTE: I did try to modify my gps location and I was unsuccessful. I only got a pokémon or two and deleted them immediately. I do apologize for trying to hack it but I'm now fully legit. Android app "Unknown error" when uploading photo Spent a half hour on this. Android 5.1.1 latest version SE app (Play Store won't let me update so latest).   Tried to upload photo into an answer. "Something went wrong".  Did tricks to reduce photo size to 275k -- same.    45k rep on the stack.  Here is the photo..... oh wait.  How do I solve? How to find image coordinates of the rendered vertex? I have a simple mesh of a cube.  I would like to know what are the coordinates of each vertex in the rendered image (i.e. for each 3d vertex I'd like to know it's pixel coordinates).  Is there a way to do this?  Clarification:  I'm experimenting with a pose estimation algorithm (i.e. finding out the 3d pose of the object) from a (set of) 2d image(s).  Instead of taking an image of a real object with a real camera I synthetically render the image of a cube using blender.  In this way I know the pose of the object and the intrinsics of the camera, so I can easily validate the results of the pose estimation algorithm. Pose estimation algorithms usually require to provide them with world points on the object and the corresponding image points.  So what I'm looking for is a way to produce a dump of correspondences of the 3d point &lt;--> image point as a byproduct of the rendering procedure. Thanks, Alex Are plants creatures or objects? This has occurred to me due to conflict between Fabricate and Blight. Fabricate says it can not target creatures and lists trees as example targets. Blight on the other hand can only target creatures and lists mundane normal plants as example targets.     Which of these conflicting spell descriptions is correct?    Note: It also occurred to me that plants might also be whichever one is convenient, unlikely but possible. How to make math font huge How to run a script without closing the terminal? I have a script in file bla.sh and it is executable. When I click on it, the script is executed and the window is closed. I'd like the window to stay open.  Something like command cmd /k** command in Windows.  P.S. I don't want to use pause, but I want to able to write more commands after the script was executed. Does a charged particle accelerating in a gravitational field radiate? A charged particle undergoing an acceleration radiates photons.  Let's consider a charge in a freely falling frame of reference.  In such a frame, the local gravitational field is necessarily zero, and the particle does not accelerate or experience any force. Thus, this charge is free in such a frame. But, a free charge does not emit any photons. There seems to be a paradox. Does a freely falling charge in a gravitational field radiate? What laptop specs are important for intensive image editing work? How important is the following in purchasing a laptop that will be used for image editing:   processor speed amount of RAM integrated vs. dedicated graphics card HD speed (SSD; or 5400/7200/10000 rpm) java math calculation for coordinates of circle given radius of 1.00 In the DC Comics Universe, What Happens to Earthlings Under a Red Sun? A company is any form of business whether it is small or large. Generally the term &quot;company&quot; indicates a particular kind of business dealing in a specific product. An organisation is the larger form and generally comprises of a number of companies.  Simply, a company is an organization, but an organization is not just a company. An industry is the combination of companies in same line of business. Firm, corporation and business  are synonyms of &quot;company&quot;. An Agency is a particular kind of company, which serves as an intermediary between clients (other companies or individuals).  Is this correct? Etymology of Tor and Ext Functors The names of the derived functors $\operatorname{Tor}$ and $\operatorname{Ext}$ seem quite cryptic to me. Does anyone know what these abbreviations stand for? I would be glad if someone could tell me where these names come from. Inverse of a diagonal matrix plus a constant I am looking for an efficient solution for inverting a matrix of the following form:  $$D+aP$$   where $D$ is a (full-rank) diagonal matrix, $a$ is a constant, and $P$ is an all-ones matrix.   gives a solution to the special case where all diagonal entries of $D$ are the same.  The  formula is also capable of providing a solution to this problem by setting appropriate $u$ and $v$, but it loses efficiency ($O(n^3)$ time complexity to compute) at high dimension. I am hoping to get a result in the same form so the space and time complexity are both $O(n)$. Probability of Obtaining the Roots in a Quadratic Equation by Throwing a Die Three Times Are there any differences between insmod and modprobe? Do I need to have antivirus software installed? I thought that there was no need to scan for viruses either in Ubuntu or any Linux distros until I found virus scanner packages clamtk and klamav in Ubuntu software center yesterday.  This leads to the following questions:   How do viruses differ between Linux and Windows? How do the strategies for protection differ between Linux and Windows? Should a virus scanner package be installed on my system? If so, which would be a better option?