My info@ email address keeps sending SPAM mails
Site being repeatedly hacked: any useful tips for tracking down entry point?
Installing from source - do I need to keep the extracted tarball directory If I'm installing from source, do I need to keep the extracted tarball directory?  So if I download the git tarball. I then do:  tar -xvzf git.tar.gz   This will create a git.x.x. directory, into which I cd, then run ./configure etc. Once I'm done with this process, and git, or whatever is installed, do I need to keep the original git.x.x extracted directory, or is that just used for compiling the program?  I'm somewhat confused by all the directories, and folders used for programs. I have a small server which I use for testing and programming. Currently it runs Debian 9.4 stretch with 4.14.0-0.bpo.3-amd64 kernel.  Today I tried to connect through SSH but I couldn't then I tried to ping it and it was unreachable. Therefore I had to hard-restart it by unplugging power cable. Then I went to  /var/log/syslog  and I found a strange line containing exactly 6140 characters like the following  ^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@  then nothing else until new log entries of system restart. This is actually the first time it happens.  Does someone know what could it be? Loading .sql files from within PHP Cron Job not working in plugin I have written a plugin that will convert posts to excel format and then email the .xls to an email id. I can make it work with when function is declared in functions.php but does not work with function defined in plugin file.   if ( ! wp_next_scheduled( 'xls_func_hook1' ) ) {   wp_schedule_event( time(), 'hourly', 'xls_func_hook1' ); }  add_action( 'xls_func_hook1', 'sendxls1' ); //senxls1 is a function in functions.php if ( ! wp_next_scheduled( 'xls_func_hook2' ) ) {    wp_schedule_event( time(), 'hourly', 'xls_func_hook2' ); } add_action( 'xls_func_hook2', 'export2excel' );   The full code is at How can I enable AHCI on a SATA drive after installing Windows? Can I enable AHCI after installing Windows 7 in a SATA drive that was on IDE mode? Will a bullet dropped and a bullet fired from a gun horizontally REALLY hit the ground at the same time when air drag is taken into account? I am trying to solve this exercise from Royden's 3rd edition.     The question is as follows: Let $f$ be a real-valued function defined for all real numbers. Show that the set of points at which $f$ is continuous is a $G_{\delta}$.    Let $$A_n = \{y : \text{there is a }~\delta_y \gt 0 : |f(s)-f(t)|\lt 1/n ~ \text{whenever}~ s,t \in (y-\delta, y+\delta)\}\;.$$     Then by the definition of open sets, $A_n$ is open.     To complete the proof, I need help in showing that $f$ is continuous at say $x$ if and only if $x\in \cap A_n$.     If $f$ is continuous at $x$, the there is a $\delta \gt 0$ such that $|f(x) - f(a)| \lt 1/n$ whenever, $x\in (a-\delta, a+\delta)$. so $x \in A_n$ son it must be in $\cap A_n$.  Thanks. Should I always use the perfect present, when the sentence uses "never"? In my English classes, I was taught that never should not be used with past forms, only with present perfect forms; this is also what I read in a grammar book I bought some years ago. (I bought the book in the USA; I guess the book is about American English grammar, but I don't have any reason to believe there is any difference between American, and British English in this case.)  Is it correct to use never with the past tense?     I never said that.        I have never said that. Order of redirections I don't quite understand how the computer reads this command.  cat file1 file2 1&gt; file.txt 2&gt;&amp;1  If I understand, 2&gt;&amp;1 simply redirect Standard Error to Standard Output.  By that logic, the command reads to me as follows:    concatenate files file1 and file2.  send stdout from this operation to file.txt. send stderr to stdout. end?   I'm not sure what the computer's doing. By my logic, the command should be   cat file1 file2 2&gt;&amp;1 &gt; file.txt   but this is not correct. If a car hits a wall at a speed of $v$, and an identical car hits a wall at a speed of $2\,v$, with the kinetic energy equation $E_K = \frac{1}{2}mv^2$ (the speed goes from $v$ to $0$) the second car will lose 4 times the energy, and therefore cause 4 times the damage, but with the force equation $F = ma$ (the car hits the wall and decelerates), it will hit with 2 times the force, and cause 2 times the damage.  How can this be explained? How do you add a thin outline? I am new at this. I am extracting files a game. In the game they have thin black outlines, but they aren't part of a model. I am having trouble finding anything about this. What is the simplest way to do this?  Update: I think I am looking for something like freestyle. What is the simplest way to use this to create a thin black outline around a model? Why doesn't the Related question list show that questions are closed? I saw a question on Meta that was obviously going to be a duplicate:        And indeed, looking at the "Related" questions list for that question showed a number of duplicates:    Being the good citizen I am, I tried to vote to close (technically Flag as duplicate as I've not got the rep here to vote to close) it as an Exact Duplicate only to find myself falling into a rabbit hole of Closed, Duplicate questions. Is there any way to flag a closed question as such in the Related list?  Mostly because the first one I picked was closed as a duplicate of the second one, which was closed as a duplicate of the one that is now listed as the duplicate/linked answer.   Edit to respond to comment:  I take the point about "not voting to close on title alone", and normally wouldn't, however as the questions had identical titles, and it's pretty clear what they should be asking, I clicked the first one:    which lead to:  which leads to:  - but I'd got bored following links and didn't check that one as the first two were identical, so assumed this was too and didn't want to see how deep the rabbit hole led.   In the related list, there's only one other question in there that is an exact duplicate, but hasn't (currently) been closed as such which is:      Reasoning for highlighting closed questions:  The "Questions with similar titles" does display the closed titles when asking the question, so it should be fairly possible to include.  If there are clearly duplicate titles, then as a reader/reviewer would be helpful to know which ones are already closed as duplicates so you can either:   Use the remaining open questions to focus on which of those is the canonical answer to close this with. Use the closed questions to find the canonical answer (which failed for me with my route of clicks). This may be a stupid or trivial question, but I am new to Ubuntu, and have two unsolved problems (flashplayer doesn't play, and scanner doesn't work - in virgin install 13.04), so I started to search in documentation. In the 13.04 specific web site I was browsing the hardware section, and came across something like this: "Open Dash, and select Disk Utilities".  So what is Dash, and where is Disk Utilities?  The application finder could not find any of those. In terminal the "dash" command seems to invoke some sort of a shell. Cycles : shadows on smooth shaded mesh, strange behavior How can I check if my (unlocked) phone will work with a particular country's SIM cards, for 3G and calls? I've used my phone overseas with local SIM cards a lot, but recently had a surprising experience where one local SIM card simply wouldn't work with my phone but did work first time on my partner's, even though both were similar (unlocked Android phones) and another SIM card from a different local provider did work. Looking into it, it looks like there are various different standards around, but it all gets very technical very quickly.  Is there any simple way of looking up which SIM cards in a particular country will work with a particular model of phone, for calls, texts and internet access? Windows 8 Setting an image on the login screen In Windows 8.1 when you log in there's the prelogin screen that has an image you can change, but then there's also the login (password entry) screen that as far as I can see is just a solid color.  How could I replace that with an actual picture? (ie, if I wanted a company logo to be displayed in the large space underneath the password entry box. Let $G$ a group with normal subgroups $M,N$ such that $M\cap N=\{e\}$. Show that if $G$ is generated by $M\cup N$ then $G\cong M \times N$. My web application generates a lot of reports in formats like excel sheet, Csv(comma-separated values), fixed width columns, pdf format, html reports etc based on the parameters I select. There is a lot of data in the reports.  Are there any essential criteria for testing report generation that I may not have considered.  I know to test these things:   Data is correct Filters are used Output format is correct   What else is there? Is it ethical to use a textbook required for a class that was easily found online? Does a correlation matrix of two variables always have the same eigenvectors?