Is there a way to kill all mobs other than /kill @e?  For some reason, it kills me too. Someone told me to do something like    /kill @e{type=Zombie}    but every time I put it in, nothing happens.
I have a Redstone Power loop that connects to a Command Block that is set to kill all entities except for myself (/kill @e[type=!Player]), because I'm building a creative map, but don't want slimes all over the place. Problem is if I want to place an Item Frame than the Command Block kills it.  So, is there anyway to exclude items from getting deleted, or make it so it will only target mobs?
Correct position of "only" Which is grammatically correct?  I can only do so much in this time.  or  I can do only so much in this time. Where does the energy required to stop a moving body come from and go? For a long time, I have been thinking about this: In order to stop a moving body, I have to apply impulse to change the existing momentum to $0$. For the impulse I have to impart force on the moving body . That means I have to eliminate all the kinetic energy associated with the moving object in order to bring it to a halt. Thus, work is done on the object, right? If work is done, energy must be given by me...  Here is where my confusion arises:   If I eliminate the associated kinetic energy of the body, where does this energy go? The work(?) done by me on the moving object to stop it obviously uses energy from me. Again, where does this energy go? Entering Unicode characters in LaTeX What does increased caster level affect? So there are several types of transistors:   BJT JFET MOSFET   Combine all that with the various flavors of each (NPN, PNP, enhancement mode, depletion mode, HEXFET, etc) and you've got a wide array of parts, many of which are capable of accomplishing the same job.  Which type is best suited for which application?  Transistors are used as amplifiers, digital logic switches, variable resistors, power supply switches, path isolation, and the list goes on.  How do I know which type is best suited for which application?  I'm sure there are cases where one is more ideally suited than another.  I admit that there is some amount of subjectivity/overlap here, but I'm certain that there is a general consensus about which category of applications each of the transistor types listed (and those I left off) is best suited for? For example, BJTs are often used for analog transistor amplifiers and MOSFETs are generally used for digital switching.  PS - If this needs to be a Wiki, that's fine if someone would like to convert it for me How to type special/accented letters in LaTeX? Moving files of specific type/extension from one directory to another? Difference between "@id/" and "@+id/" in Android I am getting an 'access is denied' error when I attempt to delete a folder that is not empty. I used the following command in my attempt: os.remove("/folder_name").   What is the most effective way of removing/deleting a folder/directory that is not empty? Why are there $736$ matrices $M\in \mathcal M_2(\mathbb{Z}_{26})$ for which it holds that $M=M^{-1}$? I'm currently trying to introduce myself to cryptography.  I'm reading about the Hill Cipher currently in the book Applied Abstract Algebra. The Hill Cipher uses an invertible matrix $M$ for encryption and the inverse matrix $M^{-1}$ for decryption. The book recommends to use a matrix $M$ for which it holds that $M=M^{-1}$, since we then have the same key for encryption and decryption.  In the book, they use a $2 \times 2$ matrix $M$ over $\mathbb{Z}_{26}$ as example, and state that for there are 736 $2 \times 2$ matrices for which it hold that $M=M^{-1}$.  I'm trying to pick up on as much as possible when reading things, since I find it counter-productive for learning to skip something, when you don't get the theory behind it. Can someone enlighten to me, as to why it is that there are 736 possible $2 \times 2$ $M=M^{-1}$ matrices and how to find them? Suppose a package provides whatever.service file so certain events (including whatever.socket) cause a daemon to start with a certain configuration.  I want to disable this completely. In particular, I want the old socket and any other unit files that might refer to this service by name to be unable to start the daemon.  Instead, I want to create my own unit files for this daemon with a different .socket unit and different environment variables. I also want my override to automatically take account of possible upstream updates to the original unit file (which my current solution of copying whatever.service as whatever-modified.service and editing it unfortunately does not provide).  If I create the following symlinks and files: /etc/systemd/system/whatever.service → /dev/null /etc/systemd/system/whatever-modified.service → /usr/lib/systemd/system/whatever.service /etc/systemd/system/whatever-modified.service.d/fix.conf  systemd considers the new service to be masked as well and refuses to start it. How to avoid this? A friend wants to use my account for a wire transfer. Is this a scam or is it legitimate? I have a friend since July online and Exxon owe him for a balance on a 2014 contract off the shores of Liverpool. He is presently in the Gulf of Mexico completing a contract that last for one year. During that year he cannot get off the boat there fore he cannot receive the money.  Exxon has notified him that his check has been deposited in Samba Bank in London. If he doesn’t receive his money within two weeks it goes back to Exxon and he said that there I not telling nohow long before he will receive the money again. He said that with him being off shore that he needs me to be his beneficiary to receive the money for him. He wants me to keep the money in my account and when he gets off the boat in 6 weeks he is relocating to where I live.  I am to buy a house before he gets here and then he wants us to start a business together. He talked with me for quite a while before he told me how much he makes. He knows I do not have any money to mention. I have stock in a formal shop but not any money.  He said if this money had not come in when it did he would have had to postpone his plan until he gets paid what Shell Oil owes him for this contract that he will finish October 15th. He said he had given enough of his life to the gas and oil industry and is not going to sign another contract.  What do you think about the safety of this? existence of complex structure in dimension 2 Does an orientable closed 2 manifold always admit a complex structure?﻿  I know that an almost complex doesn' t necessarily give rise to a complex structure(the almost complex structure should be integrable) I am studying 2 manifolds over R, and I wonder if an almost complex structure always exist? This almost structure may be chosen integrable?  I ask because there are certain known results on the different possible geometries in dimension 2.I don' t know exactly how these manifolds (closed and orientable) are classifyied, but I know there are three cases. May be I am confused, and the complex structure is irrelevant to this classification. Some help please! Details on how the Yearling badge works Jawa asked me this  and I didn't know the answer. So I present it to the meta SO community:     [To get the Yearling badge] Do you need to earn the 200 rep within that one year or is it enough to get 200 at some point after being a member for a year? And does 'a year' mean the very first 12 months or the last (sliding window of) 12 months?    I would assume that if you hit 200 reputation after you've already been around for a year, then you would get the Yearling badge. But I don't know. How do you use a variable in a regular expression? I would like to create a String.replaceAll() method in JavaScript and I'm thinking that using a regex would be most terse way to do it.  However, I can't figure out how to pass a variable in to a regex.  I can do this already which will replace all the instances of "B" with "A".  "ABABAB".replace(/B/g, "A");   But I want to do something like this:  String.prototype.replaceAll = function(replaceThis, withThis) {     this.replace(/replaceThis/g, withThis); };   But obviously this will only replace the text "replaceThis"...so how do I pass this variable in to my regex string? Why is 24.0000 not equal to 24.0000 in MATLAB? I am writing a program where I need to delete duplicate points stored in a matrix. The problem is that when it comes to check whether those points are in the matrix, MATLAB can't recognize them in the matrix although they exist.  In the following code, intersections function gets the intersection points:  [points(:,1), points(:,2)] = intersections(...     obj.modifiedVGVertices(1,:), obj.modifiedVGVertices(2,:), ...     [vertex1(1) vertex2(1)], [vertex1(2) vertex2(2)]);   The result:  &gt;&gt; points points =    12.0000   15.0000    33.0000   24.0000    33.0000   24.0000  &gt;&gt; vertex1 vertex1 =     12     15  &gt;&gt; vertex2     vertex2 =     33     24   Two points (vertex1 and vertex2) should be eliminated from the result. It should be done by the below commands:  points = points((points(:,1) ~= vertex1(1)) | (points(:,2) ~= vertex1(2)), :); points = points((points(:,1) ~= vertex2(1)) | (points(:,2) ~= vertex2(2)), :);   After doing that, we have this unexpected outcome:  &gt;&gt; points points =    33.0000   24.0000   The outcome should be an empty matrix. As you can see, the first (or second?) pair of [33.0000 24.0000] has been eliminated, but not the second one.  Then I checked these two expressions:  &gt;&gt; points(1) ~= vertex2(1) ans =      0 &gt;&gt; points(2) ~= vertex2(2) ans =      1   % &lt;-- It means 24.0000 is not equal to 24.0000?   What is the problem?    More surprisingly, I made a new script that has only these commands:  points = [12.0000   15.0000           33.0000   24.0000           33.0000   24.0000];  vertex1 = [12 ;  15]; vertex2 = [33 ;  24];  points = points((points(:,1) ~= vertex1(1)) | (points(:,2) ~= vertex1(2)), :); points = points((points(:,1) ~= vertex2(1)) | (points(:,2) ~= vertex2(2)), :);   The result as expected:  &gt;&gt; points points =      Empty matrix: 0-by-2 7 month old wants to sleep on its belly -- is it safe? PreparedStatement IN clause alternatives? Bug with Excavator Badge I edited this post today  on stack overflow. I was approved of the edit, so I waited a few minutes to get my  badge because this answer was posted on Jan 28 '10 at 1:06, but it never came. I have read multiple articles on meta that there have been bugs with this badge, but they have been about winning it multiple times (), or earning it then losing it (). Am I missing something here? Been doing tests in sandbox in which I've created about a million accountshares that I need to get rid of for testing.   I'm trying data loader in bulk api mode to export than delete but I keep getting:     InvalidBatch : Failed to process query: QUERY_TIMEOUT: Your query request was running for too long. Trying again later.;   Not sure if I should be waiting longer? Any other options or dataloader configurations I should be looking at?  EDIT  I've been trying with batch apex jobs yet still having issues.   Script  string str='select id from AccountShare where lastmodifiedbyid =\'0050P000007Kfy2\' limit 10000'; sharedeletebatch bdt=new sharedeletebatch(str); Database.executeBatch(bdt); system.debug(bdt);   Batch  global class sharedeletebatch Implements Database.batchable&lt;sobject&gt; {       global final string query;      global sharedeletebatch(string q){            query=q;      }       global Database.QueryLocator start(Database.BatchableContext BC){        return Database.getQueryLocator(query);      }      global  void execute(Database.BatchableContext BC,List&lt;SObject&gt; scope){          delete scope;      }     global void finish(Database.BatchableContext BC){     }   }      First error: [REQUEST_RUNNING_TOO_LONG] Your request was running for too long, and has been stopped.