How to know Windows Partitions?
How do I remove Windows but keep Ubuntu?
A book on quantum mechanics supported by the high-level mathematics Please suggest me any particular unnecessary file that I can clean to back everything to normal condition(temporarily). (i.e. any log or archieve or anything ). My var/log has only 40MB and Home directory has 3GB of space(so I believe that's not a problem). Other than that what I can clean up to make space.   [user@host]$ df -h Filesystem            Size  Used Avail Use% Mounted on /dev/mapper/vg_inamivm-lv_root                        18G   17G     0 100% / tmpfs                 1.9G     0  1.9G   0% /dev/shm /dev/sda1             485M   71M  389M  16% /boot   I am in a debian machine.   UPDATE1:  output of  cd /; du -sxh *  6.1M    bin 61M     boot 156K    dev 22M        etc 3.3G    home 306M    lib 18M     lib64 16K     lost+found 4.0K    media 4.0K    mnt 408K    opt du: cannot access `proc/18605/task/18605/fd/4': No such file or directory du: cannot access `proc/18605/task/18605/fdinfo/4': No such file or directory du: cannot access `proc/18605/fd/4': No such file or directory du: cannot access `proc/18605/fdinfo/4': No such file or directory 0       proc 208K    root 9.7M    sbin 0       selinux 4.0K    srv 0       sys 8.0K    tmp 536M    usr 187M    var   Update2  Output of ls -la /  dr-xr-xr-x.  22 root root  4096 Aug  7 08:42 . dr-xr-xr-x.  22 root root  4096 Aug  7 08:42 .. -rw-r--r--.   1 root root     0 Aug  7 08:42 .autofsck dr-xr-xr-x.   2 root root  4096 Mar 28 16:53 bin dr-xr-xr-x.   5 root root  1024 Mar 28 16:54 boot drwxr-xr-x.  16 root root  3580 Sep  9 03:13 dev drwxr-xr-x.  69 root root  4096 Aug 23 09:19 etc drwxr-xr-x.   9 root root  4096 Jun 29 16:10 home dr-xr-xr-x.   8 root root  4096 Mar  7  2012 lib dr-xr-xr-x.   9 root root 12288 Mar 28 16:53 lib64 drwx------.   2 root root 16384 Mar  7  2012 lost+found drwxr-xr-x.   2 root root  4096 Sep 23  2011 media drwxr-xr-x.   2 root root  4096 Sep 23  2011 mnt drwxr-xr-x.   3 root root  4096 Mar  7  2012 opt dr-xr-xr-x. 355 root root     0 Aug  7 08:42 proc dr-xr-x---.   5 root root  4096 Aug 17 18:27 root dr-xr-xr-x.   2 root root  4096 May  2 09:13 sbin drwxr-xr-x.   7 root root     0 Aug  7 08:42 selinux drwxr-xr-x.   2 root root  4096 Sep 23  2011 srv drwxr-xr-x.  13 root root     0 Aug  7 08:42 sys drwxrwxrwt.   3 root root  4096 Sep 13 03:37 tmp drwxr-xr-x.  13 root root  4096 Mar 28 17:53 usr drwxr-xr-x.  18 root root  4096 Mar  7  2012 var Why do I have to say “want you to do” instead of “want you do”? I'm confused about 'want you to do (something)' and 'want you do (something)'.  Example:      "I want you to eat fish" instead of "I want you eat fish" or "I want that you eat fish".    Can anyone explain what is the grammar rule for this? I needed to create a list of lists in Python, so I typed the following: my_list = [[1] * 4] * 3  The list looked like this: [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]]    Then I changed one of the innermost values: my_list[0][0] = 5  Now my list looks like this: [[5, 1, 1, 1], [5, 1, 1, 1], [5, 1, 1, 1]]    which is not what I wanted or expected. Can someone please explain what's going on, and how to get around it? Solving a Linear Diophantine Equation A Linear Diophantine Equation is of the following form:                                                                                        $Ax+By+C=0$, where $x_1 \leq x \leq x_2$ and $y_1 \leq y \leq y_2$.  If the value of $A,B,C,x_1,x_2,y_1,y_2$ are given and $x_1 \leq x_2$ and $y_1 \leq y_2$, then how many solutions can be found? How can I find out the total number of solutions according to the above condition. I have to give a combinatorial proof of  $$\sum_{k=1}^nk{n\choose k}^2=n{2n-1\choose n}.$$  I find it difficult to solve such problems. I'm not a brilliant person and never will be so I need to have algorithms to solve most problems. Usually I won't just "see" solutions unless I have a thorough enough understanding of a theory. This is also the case here. I know what the symbols mean, but I don't see what I should count and how to obtain the identity.  I think the right-hand side counts $n$-element subsets of a $(2n-1)$-element set with one element chosen to be "special". I think I should find a partition of the set of such subsets into $n$ parts so that the left-hand side is the sum of the cardinalities of the parts. Is there $n$ of anything on the right-hand side? Well, there are $n$ choices for the "special" elements, but only after I've chosen the $n$-element subset. Otherwise I can choose the "special element" in $2n-1$ ways.  This is a homework problem so I probably shouldn't ask for a full solution. But I would like to have some guidelines for approaching such problems, perhaps based on this example. Merge some tab-delimited files I have a requirement to implement an "Unsaved Changes" prompt in an ASP .Net application.  If a user modifies controls on a web form, and attempts to navigate away before saving, a prompt should appear warning them that they have unsaved changes, and give them the option to cancel and stay on the current page.  The prompt should not display if the user hasn't touched any of the controls.  Ideally I'd like to implement this in JavaScript, but before I go down the path of rolling my own code, are there any existing frameworks or recommended design patterns for achieving this?  Ideally I'd like something that can easily be reused across multiple pages with minimal changes. I have a 2 year old son and another baby on the way. I just recently found out I'm pregnant but not sure how far just yet. My son rammed into my stomach like he is always doing but this time it made me start having small pains in my stomach. I rushed to the bathroom to make sure there wasn't any bleeding.  I'm concerned his rough play could hurt the fetus if it continues. How should I put a stop to it? Why can't I capture my first Pokemon? I'm trying to just catch my first Pokemon and I can't for some reason. From what I've read I should be able to see the three basic Pokemon to choose from and catch one but I can't see them.  I can only see three pulsing circles and the app appears to be stuck on map view. I've tried clicking or walking over the circles but nothing happens.   Any suggestion on how to fix this? What is an intuitive explanation for how PCA turns from a geometric problem (with distances) to a linear algebra problem (with eigenvectors)? 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 to see time stamps in bash history? Is there any way I can see at what time the commands were executed from the bash history? We can see the order but is there any way I can get the time also?  Bottom-Line: Execution time in the Bash history How can I find out what is using the hard disk? Possible Duplicates:             Once or twice a day my computer starts writing significantly hard to the hard drive, the HD led is ON and the performance hit is noticeable. A strange observation is that the Task Viewer does not show I/O activity - even Process Explorer shows no CPU activity and no I/O bytes read or written.  Is there a way to know which application is using the hard drive and how much data is it reading or writing? Are there any stats about the percentage of close reasons used to close questions   Successfully (preferably, based on the number of closed questions) Unsuccessfully (alternatively, the total percentags of close votes cast by users)   ?   Is there any way to get this from the query explorer? How to exit early on pipe close? I use golang for writing programs that are too complex to express as bash functions. The programs read stdin line by line and write modified output to stdout.  The problem with this iterating over all the lines in stdin approach, is that it doesn't exit early. For example, the following command will process all the lines instead of just 10:  cat largefile | custom-program | head -n 10   How do the native unix application manage to exit early and how can I do the same in my custom scripts? What is the purpose of the three part circuit? I'm studying for my final on introduction to circuits and came across a question about this circuit:  The question is:  Identify and describe the three parts of the circuit used for a measurement system for signal conditioning. Describe the signal conditioning one intends to use the circuit for.  From what I can tell the R1 and R2 resistors are the first part of the circuit used to use a fraction of the incoming voltage. The second part is the voltage follower used to move all of the incoming voltage to another circuit. Lastly there is a low pass filter used to filter off the high frequency voltage. The second question I'm not sure of the answer. Charging lead-acid batteries? "Economic" vs. "economical" How should I address a potential FERPA violation by a professor? In the United States, federal law prohibits professors from releasing any student's grades to any party other than the student and any party whom the student authorizes to receive the grades.  One of my professors appears to be violating this law by uploading each student's lab grades in one file, which is accessible to anyone who is enrolled in the class.  Here is my proposed plan of action:   Ask the professor - in private - to post the grades using the online management system the professor already uses for other things.  If the professor doesn't fix this privacy violation, inform the professor that the method by which he/she post grades is a violation of federal law. As a last resort, contact the department dean. How to upload a file to a WCF Service? I've build a WCF Service to accept a file and write it to disk. The front-end consists of a page with SWFUpload which is handling the upload on the client side. Apparently, SWFUpload posts the data with a Content Type of: multipart/form-data.  I would think this ok but on the Service side I get an error. The error is "ProtocolException" expecting text/xml. I've tried different message encodings in the bindings but nothing seems to work.  How can I get this file uploaded using multipart/form-data?