My hard drive appears to be filling itself up by itself. Every time I delete files, it immediately fills up. I do not have back up enabled either. I don't even download much. I mostly stream. The only thing that autodownloads is variety.
I recently wiped my computer to have 14.10 as my only OS. It has 160 GB of storage. That was a month ago. Now, I keep getting prompts that the storage is almost full. And when I look it says I only have 543 MB free. How is this possible? I haven't torrented any large files. I do have Variety to autodownload wallpapers and not erase though.  Filesystem Size Used Avail Use% Mounted on  /dev/sda1  146G  138G  554M  100%  /  none 4.0K 0 4.0K 0% /sys/fs/cgroup  udev 742M 4.0K 742M 1% /dev  tmpfs 151M 1.1M 150M 1% /run  none 5.0M 4.0K 5.0M 1% /run/lock  none 752M 540K 751M 1% /run/shm  none 100M 80K 100M 1% /run/user –  er –
How to count derangements? I was going through .Suppose that there are n persons who are numbered 1, 2, ..., n. Let there be n hats also numbered 1, 2, ..., n. We have to find the number of ways in which no one gets the hat having same number as his/her number. Let us assume that the first person takes hat i. There are n − 1 ways for the first person to make such a choice. There are now two possibilities, depending on whether or not person i takes hat 1 in return:  A) Person i does not take the hat 1. This case is equivalent to solving the problem with n − 1 persons and n − 1 hats: each of the remaining n − 1 people has precisely 1 forbidden choice from among the remaining n − 1 hats (i's forbidden choice is hat 1).  B) Person i takes the hat 1. Now the problem reduces to n − 2 persons and n − 2 hats.  From this, the following relation is derived: !n = (n - 1) (!(n-1) + !(n-2))  I have a hard time understanding point B and the equation derived. I was trying to understand with an example of 4 people named A, B, C and D and the corresponding hats A, B, C and D. Everyone of them are supposed to wear any hat except their own matching hat i.e. A can wear B, C or D.  If suppose A wears B hat so we will be left with only 3 people and 3 hats. So I can understand "(n-1)!(n-1)" part but what i didn't understand is part B(marked above). Can anyone help? In the Deadpool movie when Wade his mutant cells get activated, his skin changes so he looks like Freddy Krueger (As Weasel referred too). But he obtains healing abilities and his cancer gets cured because of it. He's become an immortal person which can heal any wound super fast.  What I don't understand is, why doesn't his skin heal so he would look like before? I remember that Francis (or Ajax) said that it's a 'side-effect' of mutating, but why wouldn't it heal when he has a healing ability? When I restart httpd, I get the following error.  What am I missing?  [root@localhost ~]# service httpd restart Stopping httpd:                                            [  OK  ] Starting httpd: Syntax error on line 22 of /etc/httpd/conf.d/sites.conf: Invalid command 'SSLEngine', perhaps misspelled or defined by a module not included in the server configuration   I have installed mod_ssl using yum install mod_ssl openssh  Package 1:mod_ssl-2.2.15-15.el6.centos.x86_64 already installed and latest version Package openssh-5.3p1-70.el6_2.2.x86_64 already installed and latest version   My sites.conf looks like this  &lt;VirtualHost *:80&gt; #    ServerName shop.itmanx.com     ServerAdmin webmaster@itmanx.com      DocumentRoot /var/www/html/magento     &lt;Directory /var/www/html&gt;         Options -Indexes         AllowOverride All     &lt;/Directory&gt;      ErrorLog logs/shop-error.log     CustomLog logs/shop-access.log &lt;/VirtualHost&gt;  &lt;VirtualHost *:443&gt;     ServerName secure.itmanx.com     ServerAdmin webmaster@itmanx.com      SSLEngine on     SSLCertificateFile /etc/httpd/ssl/secure.itmanx.com/server.crt     SSLCertificateKeyFile /etc/httpd/ssl/secure.itmanx.com/server.key     SSLCertificateChainFile /etc/httpd/ssl/secure.itmanx.com/chain.crt      DocumentRoot /var/www/html/magento     &lt;Directory /var/www/html&gt;         Options -Indexes         AllowOverride All     &lt;/Directory&gt;      ErrorLog logs/shop-ssl-error.log     CustomLog logs/shop-ssl-access.log     &lt;/VirtualHost&gt; How do you reverse a string in place in C or C++? How do you reverse a string in C or C++ without requiring a separate buffer to hold the reversed string? How to prevent form from being submitted? ActiveResource timeout not functioning $\aleph_0$ is the cardinality of the set of natural numbers, $\aleph_0 = |N|$. $c$ is the cardinality of the continuum, i.e. the set of real numbers $c = |R|$.  I know that $|P(A)| = 2^{|A|}$. This means that the cardinality of the power set of a set is 2 raised to the power of the cardinality of that set.  This basically means that to prove  $2^{\aleph_0} = c$, I need to prove $c = |P(N)|$. I've seen the Cantor diagonal argument, although I have no idea on how to use it to prove this.   Could anyone suggest ideas of the simplest way to prove that $2^{\aleph_0} = c$? How to find out when an Oracle table was updated the last time Can I find out when the last INSERT, UPDATE or DELETE statement was performed on a table in an Oracle database and if so, how?  A little background: The Oracle version is 10g. I have a batch application that runs regularly, reads data from a single Oracle table and writes it into a file. I would like to skip this if the data hasn't changed since the last time the job ran.  The application is written in C++ and communicates with Oracle via OCI. It logs into Oracle with a "normal" user, so I can't use any special admin stuff.  Edit: Okay, "Special Admin Stuff" wasn't exactly a good description. What I mean is: I can't do anything besides SELECTing from tables and calling stored procedures. Changing anything about the database itself (like adding triggers), is sadly not an option if want to get it done before 2010. Time-Stream Crossing and Forgetfulness In The Day of the Doctor, it's explained that the Doctor doesn't remember having interacted with himself, and if he interacts with a future version of himself, the younger version forgets.  But in Time Crash, 10th solves the problem of the TARDISes occupying the same space because he remembers himself doing it from when he was 5th.  If this is true, 5th wouldn't have wondered whether or not he was going to regenerate when he did.  Does the TARDIS occupying the same space with itself re-instate those memories? Or is it just possible that I'm asking a ridiculous question that will never have an answer because Doctor Who.  :D I am starting to learn using blender, and at some point I managed to do something to the 3D view camera.  Usually the camera orbits around an object, but now the rotation seems to happen (atleast very close to) around the "camera's origin". Neither the input setting in "User Preferences", the pivot point selection nor Ctrl-Alt-Shift-C (as suggested on some forum) do anything to the issue. I've read a lot about PCA, including various tutorials and questions (such as , , , and ).   The geometric problem that PCA is trying to optimize is clear to me: PCA tries to find the first principal component by minimizing the reconstruction (projection) error, which simultaneously maximizes the variance of the projected data.    When I first read that, I immediately thought of something like linear regression; maybe you can solve it using gradient descent if needed.  However, then my mind was blown when I read that the optimization problem is solved by using linear algebra and finding eigenvectors and eigenvalues. I simply do not understand how this use of linear algebra comes into play.  So my question is: How can PCA turn from a geometric optimization problem to a linear algebra problem? Can someone provide an intuitive explanation?  I am not looking for an answer like  that says "When you solve the mathematical problem of PCA, it ends up being equivalent to finding the eigenvalues and eigenvectors of the covariance matrix." Please explain why eigenvectors come out to be the principal components and why the eigenvalues come out to be variance of the data projected onto them  I am a software engineer and not a mathematician, by the way.  Note: the figure above was taken and modified from . How do you carry a dog on a bike? Over the years I have seen a few people transport a dog on a bike.  What options have you seen?   Please include a photo in your answer if possible. Proof by induction that $ 169 \mid 3^{3n+3}-26n-27$ $ 169$ | $3^{3n+3}-26n-27$ ?  Fulfilled for $n=0$. Induction to $n+1$: An integer $x$ exists so that  $ 169x= 3^{3n+6}-26n-27-26$ $ 169x= 27*3^{3n+3}-26n-27-26$ $ 169x= 26*3^{3n+3}+3^{3n+3}-26n-27-26$  An integer $m$ exists so that   $ 169x= 26*3^{3n+3}+169m-26$ ($ 13x= 2*(3^{3n+3}-1)+13m$)  Now I'm stuck although it looks simple. Thanks for any input in advance. So I came across this exercise: Show that if $Y$ is path-connected then the set of homotopy classes $[I,Y]$ of maps of $I=[0,1]$ into Y has a single point.   But I am confused here. If $Y=S^1$ then not all loops are homotopic! I mean, isn't true that $\pi_1(Y)\subset [I,Y]$? Or maybe I don't understand the set $[I,Y]$ well! What is a command to compile and run C++ programs? I am  new to Linux. I am using Ubuntu 11.04 and do not know how to compile and execute C++ program in it. I need to know the commands to Compile and Execute a C++ program in Linux. What techniques, tricks or otherwise have you used to get upgrades on flights? I've travelled a lot.  Living in New Zealand or the UK means anywhere is likely a flight, but I've always flown economy.  Twice between LA and Auckland I managed to get the exit row after talking nicely to the check-in girl, but apart from that, nothing.  I've spoken to ticket agents, tried 'check in chicken' (where you wait until the last minute before checking in, hoping there's an overbooking of economy) but have never managed to get an upgrade, while others I know seemingly get them quite often.  What strategy have you used or do you suggest to achieve this?  My next flight is from Melbourne to Tokyo, and I plan on trying all of these ;)  (Related questions on  and  upgrades) I've found several posts with this same question, but the answers always diverge to some other topic or they don't work for my needs.  After a node is saved, I want my custom module to insert a row into one of my custom tables which contains the nid of the new node. When hook_node_submit is called, the nid doesn't exist yet. hook_node_insert does have the nid, but only gets called the first time the node is saved, but I potentially need to take action each time the node is saved.   My plan is to separate my functionality into its own method and implement both hooks, but I'm trying to learn to do things properly with Drupal and so I'm wondering if there is a hook that actually fits with my requirements.  Is there a hook which is called every time a node is saved and called AFTER the save is complete? $x^{x^{x^{\dots}}}=2$, what is the value of $x$? I came up with this little simple exercise, stating:  $x^{x^{x^{\dots}}}$ infinite times is equal to $2$, find $x$.   As we're dealing with infinity, we can just separate the first $x$ and get $x^2=2 \implies x=\sqrt2$  But then I thought what if we change $2$ to $4$? Now we get $x^4=4 \implies x=\sqrt[4]4=\sqrt2$  Something went wrong, can someone explain? If I push or hit an object in space will it rotate or move along a straight line? I saw this several times in different movies, but I don't understand what is this supposed to mean. The main idea is when the scene is about to change, for one second or so we still see the picture from the old scene, but the sound is already coming from from the upcoming scene. Why do they do this? What's the purpose of this technique?