could someone explain the outcome entries into a file?
What does the second column in the output of 'ls -n' mean?
What are review tests (audits) and how do they work? I recently received this rather amusing message while reviewing a user's first post:  Congratulations! This was only a test, designed to make sure you were paying attention. This post has already been removed, but thanks for taking time to leave feedback for the author.   What is the purpose of this test? How does the audit work? What happens if I fail? Why was the system expecting me to negatively review a good post, or positively review a bad post? A review is obviously an audit. Should I report it? Do review audits count toward the Reviewer badge? Do robo-reviewers dream of electric sheep? Getting Joker from the existing groups in Rummikub I have a group of tiles made up of 3 fours and a joker:     4 4 4 Joker   Now, if a player removes the joker, do they have to replace it with another 4? Is there Ubuntu's analogue of snapshot.debian.org? Could someone please explain? I couldn't find anything on the internet, everything talks about how to go about it in some way, but nothing says exactly what it is.   Also, what is a fully trusted assembly and how do they differ from one another?  I have a MS certification exam and this is the only topic that I just don't understand.  EDIT: Thanks guys. Now I have a better understanding of security in .NET. I was able to pass my certification exam. How to adjust the breaking in the bibliography? doGet and doPost in Servlets I have to design a circuit in which I have to transfer data through lasers (serial transmission of data). Now what I was thinking was to check if the laser light is on then '1' is passed and when the laser is off '0' would be passed. Now I need to check if a 1 or a 0 was passed.   How would I check for this and another problem I'm facing is if it's on it may keep on passing 1's. How would I check for this? I though of using LDR's (Light Dependent Resistors)? Would this be okay or it there a better method? If an object is large enough and slow enough is there a point that we can say we know its position and momentum? I have downloaded and extracted the packet tracer file, then I used this command as root  chmod +x install   then I ran (as root)  ./install    Then I used this command   ./set_ptenv.sh   but whenever I run this command   packettracer    it just doesn't start What is the difference between select count(*) and select count(any_non_null_column)? I seem to remember that (on Oracle) there is a difference between uttering select count(*) from any_table and select count(any_non_null_column) from any_table.  What are the differences between these two statements, if any? Unicoin Bug: Automining Returns Diminishing I'm using the auto-mining script from one of the meta posts here and it doesn't works!  At first I got steady returns but the returns seem to diminish over time. Using Fiddler I confirmed that the server seems to release less and less coins.  This is unacceptable! I am a loyal customer paying nothing and I demand that my auto-mining script continues to yield returns forever!  If you cannot deliver on that please refund what I have payed for using this site.  Plz advise!    In case you didn't notice: This is a parody of over-demanding, leeching askers on Stack Overflow. Removed Windows 7 and installed Ubuntu Server 12.04, but Windows Boot Manager still appears The batcave, in any version of Batman, is large.  Plus there's the batmobile, which required special construction, plus the batcomputer and numerous other batwidgets.  How did a good sized batcave get built without the land above it being torn up and without requiring a huge construction crew?  And, after the cave was built, how was the batmobile built in secret, without someone involved in it being able to make the connection between the car they built and the one that shows up in the news when Batman is first seen?  (While he's in Gotham, a masked vigilante is news that would end up nation wide.)  There would also be the need for secrecy so vilains can't find out how it is built and what the specs are.  And then there's the continual supply of batwidgets.  Just as with the batmobile, there's the need for these items and how they work to be kept secret.  It'd take several factories to produce all that Batman uses and major construction for any batcave I've seen (which is in movies and on TV).  How is all this done in secret?  (Or is there a trail of bodies?) Multi-Question Questions: How Best to Handle Them? Sometimes I come across a question on SO that is actually a number of questions all in one. If these &quot;sub-questions&quot; are closely related, it's not a problem. But if they are only weakly related (or not at all) it gets ugly. I'm now (ironically or hypocritically) going to ask a few questions of my own for the community to respond to:  Do you consider a question made up of a number of weakly-related sub-questions &quot;inappropriate&quot;? Why or why not? How many is too many sub-questions? What do you think is the best way to deal with such questions?  As an example,  I had some discussion about with another user. I will add a more complete version of my response in an answer below, but in short I felt that this question should be closed and many of the questions asked separately. I'm trying to use grep to show only lines containing either of the two words, if only one of them appears in the line, but not if they are in the same line.  So far I've tried  grep pattern1 | grep pattern2 | ... but didn't get the result I expected. for a $3 \times 3$ matrix A ,value of $ A^{50} $ is I f $$A= \begin{pmatrix}1&amp; 0 &amp; 0 \\  1 &amp; 0 &amp; 1\\ 0 &amp; 1 &amp; 0 \end{pmatrix}$$  then $ A^{50} $  is   $$ \begin{pmatrix}1&amp; 0 &amp; 0 \\  50 &amp; 1 &amp; 0\\ 50 &amp; 0 &amp; 1 \end{pmatrix}$$ $$\begin{pmatrix}1&amp; 0 &amp; 0 \\  48 &amp; 1 &amp; 0\\ 48 &amp; 0 &amp; 1 \end{pmatrix}$$ $$\begin{pmatrix}1&amp; 0 &amp; 0 \\  25 &amp; 1 &amp; 0\\ 25 &amp; 0 &amp; 1 \end{pmatrix}$$ $$\begin{pmatrix}1&amp; 0 &amp; 0 \\  24 &amp; 1 &amp; 0\\ 24 &amp; 0 &amp; 1\end{pmatrix}$$   I am stuck on this problem. Can anyone help me please............... Why does ('0' ? 'a' : 'b') behave different than ('0' == true ? 'a' : 'b') gedit: search and replace with regular expressions I want to replace this with gedit:   1299465 |  2003415 | 2015-09-06 05:35:34.59662+02  1299449 |  2009400 | 2015-09-06 05:35:32.301683+02  1299450 |  2008465 | 2015-09-06 05:35:32.451393+02  1299457 |  2015211 | 2015-09-06 05:35:33.451049+02   to that:  2003415 2009400 2008465 2015211   How can I do this with gedit?  Background: I want to do it with gedit and not sed/python/.... since the replace needs to be done interactive. Show default image when no uploaded image rails - outputting user input with Paragraph Returns?