I had the idea a few days back to make a portable hard drive that boots Linux. That way I can keep programs with me. The problem is, I can't install an OS because drivers won't work between computers. I tried this with UbuntuGNOME, and I got ERR2ERR3 when I tried to boot.  After researching online I found that a persistent Ubuntu live USB will work perfectly. The problem is, none of the USBs that I made have actually been persistent. I made one with UbuntuGNOME and Ubuntu Desktop. They boot fine, and I can change settings, install programs, and make files. Then, after shutting down and turning back on, all my changes were reverted.  Any help with creating a persistent Ubuntu live USB or any suggestions for what I am trying to accomplish would be greatly appreciated.
After many unsuccessful trials based on almost everything about this topic on the Internet, I decided to ask this question again. There is almost  in this platform, but it did not work. That's why I am here.  I want to have Ubuntu 18.04 installed on my USB memory stick (SanDisk Cruzer Glide 32GB) with a persistent storage of more than 4GB (at least 23GB in my case).  I used MiniTool partition wizard to format the stick (NTFS) on Windows. Then, I used Universal USB Installer 1.9.8.2 to install Ubuntu 18.04 on the stick. Here, I tried to format the stick either fat32 or ntfs, but nothing changed. Later, I used another Ubuntu to delete the casper-rw file and create another partition with the same name by following the steps given in the link given above. Unfortunately, I couldn't make it working although I tried almost all combinations.  Can anyone give a thorough list of steps to follow in order to install it on the stick properly?  Edit: I gave ear to @c-s-cameron 's comment below and used YUMI to do that, and it worked. I believe all other answers would work, but I dont have time to give a try for all of them. Thanks all, again!
Is $x^x=y$ solvable for $x$? Another Question in Hatcher My friend and I were discussing this and we couldn't figure out how to prove it one way or another.  The only rational values I can figure out for $\sin(x)$ (or $\cos(x)$, etc...) come about when $x$ is some product of a fraction of $\pi$.  Is $\sin(x) $ (or other trigonometric function) necessarily irrational if $ x $ is rational?  Edit: Excluding the trivial solution of 0. echo "-e" doesn't print anything I'm using GNU bash, version 3.00.15(1)-release (x86_64-redhat-linux-gnu). And this command:  echo "-e"    doesn't print anything. I guess this is because "-e" is one of a valid options of echo command because echo "-n" and echo "-E" (the other two options) also produce empty strings.  The question is how to escape the sequence "-e" for echo to get the natural output ("-e"). Apply SP3 on SQL Server 2012 AlwaysOn AAGs Hide parameterless constructor on struct Installing Cygwin packages from the command-line I recently installed Ubuntu 17.10, and when I tried to set my keyboard layout to change with alt+shift, I hit a . There is  which works, but then it creates an unwanted behaviour on Firefox (perhaps other programs as well).   After setting alt+shift through gnome-tweak-tool as the combination to change language, whenever this combination is pressed within Firefox, it triggers a toggle that Firefox uses to show/hide the Menu Bar (with File/Edit/View etc.), and 'focus' is taken away from wherever the cursor was.   It's very frustrating, because one has to go and click again at the cursor.  The only solution I found was to permanently enable Menu Bar in Firefox because then alt doesn't do anything and I can use it to change languages. But I don't want to have Menu Bar on top always.  I hope you can understand what I'm trying to explain.  Any thoughts? I am trying to write a bash script for testing that takes a parameter and sends it through curl to web site.  I need to url encode the value to make sure that special characters are processed properly.  What is the best way to do this?    Here is my basic script so far:  #!/bin/bash host=${1:?'bad host'} value=$2 shift shift curl -v -d "param=${value}" http://${host}/somepath $@ If I'm floating in space and I turn on a flashlight, will I accelerate? Photons have no mass but they can push things, as evidenced by .   Can photons push the source which is emitting them? If yes, will a more intense flashlight accelerate me more? Does the wavelength of the light matter? Is this practical for space propulsion? Doesn't it defy the law of momentum conservation?  Note: As John Rennie mentioned, all in all the wavelength doesn't matter, but for a more accurate answer regarding that, see the comments in  .  Related Wikipedia articles: , Can I access private members from outside the class without using friends? Prove that if prime $p$ divide $a_{2k}-2$, then $p$ divide also $a_{2k+1}-1$. Minimum requirements of Ubuntu 20.10 Does anyone know what are the minimum requirements to install Ubuntu 20.10? the slash (/) after a directory name on shell commands I have a little question here.  If I have two files, say filea and fileb, mv filea fileb would   delete fileb rename filea to fileb   Then if I have two directories, say dira and dirb, mv dira dirb would   move dira into dirb (it will become dirb/dira)   Noting that in both cases there are no notice or message, then this is pretty inconsistent to me. I think mv dira dirb should just overwrite dirb with the contents of dira (or merge the two directories under a directory named dirb).  I remember reading somewhere that a directory name with a slash (like dira/) is treated like a directory, and name with no slash (like dira) is treated like a file (to certain extents, of course). Anyway now I want to make the shell (zsh and possibly bash) respect my notation of a directory by using a slash. Is there a terminal option which enable me to enforce that?  To clarify, here is my desired behaviour:   mv dira dirb results in dirb being overwritten with the contents of dira mv dira dirb/ results in dira being moved into dirb (in dirb/dira)   Has anyone thought the same way as me? Or am I just weird? I was writing test classes for my apex Rest Service that I had built for an Ipad app.  I noted some very interesting things while experimenting. Before doing anything, I just did a google search and found an interesting blog post by Jeff.    @RestResource(urlMapping='/v.9/member/*/results/*')  global with sharing class MemberRestSvc {  @HttpGet  global static ReturnClass doGet() {  String[] uriKeys = RestContext.request.requestURI.split('/'); // get the member name from the uri String memberName = uriKeys.get(uriKeys.size()-3);  // do awesome programming stuff here &amp; catch any exceptions try {    List&lt;Contact&gt; contacts = [Select Id From Contact where member_name__c = :memberName];   return new ReturnClass('true', 'Query executed successfully.', contacts);  } catch (Exception e) {   return new ReturnClass('false', e.getMessage(), null); }   }   global class ReturnClass {  global String success; global String message; global List&lt;Contact&gt; records;    global ReturnClass(String success, String message, List&lt;Contact&gt; records) {   this.success = success;   this.message = message;   this.records = records;  }  }  }   And here is the test class  @isTest private class Test_MemberRestSvc {  static { // setup test data   }  static testMethod void testDoGet() {  RestRequest req = new RestRequest();  RestResponse res = new RestResponse();  req.requestURI = 'https://cs9.salesforce.com/services/apexrest/v.9/member/me/results/today';   req.httpMethod = 'GET'; RestContext.request = req; RestContext.response = res;  MemberRestSvc.ReturnClass results = MemberRestSvc.doGet();  System.assertEquals('true', results.success); System.assertEquals(10, results.records.size()); System.assertEquals('Query executed successfully.', results.message);  }  }   I just commented a few lines and ran and it. I still achieved enough test coverage so my question is why do I need to simply instantiate the Rest request and response objects since I am directly calling the class?    @isTest   private class Test_MemberRestSvc {    static {     // setup test data     }  static testMethod void testDoGet() {  /*RestRequest req = new RestRequest();  RestResponse res = new RestResponse();  req.requestURI =    'https://cs9.salesforce.com/services/apexrest/v.9/member/me/results/today';   req.httpMethod = 'GET'; RestContext.request = req; RestContext.response = res; */Commented the code meant for REST apex intialization and merely calling the method!!  MemberRestSvc.ReturnClass results = MemberRestSvc.doGet();  System.assertEquals('true', results.success); System.assertEquals(10, results.records.size()); System.assertEquals('Query executed successfully.', results.message);  }  }   Can someone explain this behavior? Also what are the best practices for writing Test classes for apex Rest services? SSL certificate for a public IP address? I'm trying to make a command that creates a book that has many items with enchantments at level 1,000. However, I don't know why it keeps saying:     Data tag parsing failed: Unbalanced quotation:   {ench:[{id:0,lvl:1000}],Unbreakable:1,display:{Name:"Prot   It's supposed to say "Protection Armor", but it only shows "Prot" for some reason. This is the same with all of my other items. Here is the one part of the command that I've showed you:  {ench:[{id:0,lvl:1000}],Unbreakable:1,display:{Name:"Protection Armor"}} Prettify OS X console by coloring output? OS X terminal is not using colors for highlighting output from different commands, for example ls.   When compared with other systems like Ubuntu, this is a big loss of accessibility/productivity.  What solutions do I have to improve this experience? For the moment I found only this guide for  but I am looking for a more complete solution. What sources of randomness can be made with commands in Minecraft? I want to make a mini game in Minecraft were I need a random command generator for 9 commands. I need a random command to give the player a random item. I can't do the command block in the dispenser any more because it will just drop out instead of being placed. What different ways are there for generating randomness in commands, and which one would be best for my use? This question is similar to the one about , but I am specifically attempting to get randomness when using commands - the redstone solutions do not apply here. How to create a random math problem in LaTeX? I want to create a math problem-solution sheet. The coefficients a, b, c must be assigned on the fly at random so the generated pdf will show a numeric quadratic equation rather than a symbolic quadratic equation. Note a must not be zero.  \documentclass{article} \begin{document} \section{Problem} Let \(x_1\) and \(x_2\) be the roots of \(a x^2 +bx +c=0\). Find  \(x_1x_2\).  \section{Solution} \[ x_1x_2=\frac{c}{a} \] \end{document}   Please kindly make the solution get automatically simplified. For example: \frac{c}{a}=3 when a=2 and c=6.    Actually the real case is more complex than this one. Not only the equations must be generated at random, but also the associated graphic plots that I write in PSTricks.     I chose Paulo's answer because using Maxima as the computation engine is very very great idea. Other answers are also good and creative, especially Altermundus'.