Why does every installation tutorial ask me to update?
What does "sudo apt-get update" do?
Is floating point math broken? Consider the following code:   0.1 + 0.2 == 0.3  -&gt;  false   0.1 + 0.2         -&gt;  0.30000000000000004   Why do these inaccuracies happen? How can the following inequation be proven?  $$a^2 + b^2 + c^2 \ge ab + bc + ca$$ Let a,b,c,d be real or complex numbers with absolute value less than $1$. Is the following true:  $$|ab-cd| \leq |a-c| +|b-d|?$$ Distant aliens receive signal with instructions on how to construct humans, long after Earth is extinct Removing minimize/maximize buttons in Tkinter I am trying to pass the email value from a data extension to HTML. I am using the CloudPagesURL() in my email in attempt to grab the subscriber's email.  Here is my code syntax that I am attempting to use:  Email Code:  &lt;p&gt;&lt;a title="MyPage" href="%%=RedirectTo(CloudPagesURL(505,'Email Address',@EmailAddress))=%%" alias="ThisAlias" conversion="false"&gt;Click to unsubscribe page 505&lt;/a&gt;&lt;/p&gt;   CloudPage AMPScript Code:  %%[  VAR @emailAddress  SET @emailAddress = RequestParameter("emailaddr")  ]%%   Cloudpage HTML Code:  &lt;td width='155' valign='bottom'&gt;&lt;input type='text' name='Name1' value='%%=v(@emailAddress)=%%' id='Name1' /&gt;&lt;/td&gt;   Any reason as to why this doesn't work? My syntax might just be wrong or I might be using the CloudPagesURL() function incorrectly. How do I extract an ISO on Linux without root access How to concatenate text from multiple rows into a single text string in SQL server? Consider a database table holding names, with three rows:  Peter Paul Mary   Is there an easy way to turn this into a single string of Peter, Paul, Mary? I'd like to be able to search for questions by multiple tags; for example "questions tagged 'nhibernate' and 'web-services'".  I can get close by searching for "nhibernate web-services" but the results tend to be a few questions that relate to both terms--but much more largely just questions that relate to one or the other. Some Windows 10 UWP icons not displaying on search, or in settings Breakthrough at the Large Hadron Collider -Leptoquarks skepticism? Google Voice Recognition on iOS Does $\mathbb R^2$ remain connected when countably many points are removed? Does it remain path connected?  This is not homework but is in response to working several problems where countable or uncountable many points are removed and the pattern always holds.  Thank you. How to iterate over arguments in a Bash script I have a complex command that I'd like to make a shell/bash script of.  I can write it in terms of $1 easily:  foo $1 args -o $1.ext   I want to be able to pass multiple input names to the script. What's the right way to do it?    And, of course, I want to handle filenames with spaces in them. What translation occurs when writing to a file that was opened in text mode that does not occur in binary mode? Specifically in MS Visual C.  unsigned char buffer[256]; for (int i = 0; i &lt; 256; i++) buffer[i]=i; int size  = 1; int count = 256;   Binary mode:  FILE *fp_binary = fopen(filename, "wb"); fwrite(buffer, size, count, fp_binary);   Versus text mode:  FILE *fp_text = fopen(filename, "wt"); fwrite(buffer, size, count, fp_text); How to solve this recurrence $T(n) = 2T(n/2) + n\log n$ How can I solve the recurrence relation $T(n) = 2T(n/2) + n\log n$? It almost matches the Master Theorem except for the $n\log n$ part. What is the relationship between lands and mana in Magic and what do each of them do?  A good answer should especially include how a new player should think about them.    Note:  This is an attempt to create a canonical question about the relationship between lands and mana in Magic.  Beginners are often confused about this given the same symbols are used to mean different things across basic lands, non-basic lands, and mana costs.  This can lead to confusion about , about , or even about . I want to include something in my LaTeX article that will make all mathematical formulae appear in black, while all text (including everything inside \text{}s in the middle of mathematical formulae) appear in red.  Ideally I would like this to be something I could include in the preamble or in a .cls file or something like that.  What would be the quickest way to do that? I've got a very large document (which I've broken into "chapters" and such) which I've recently moved a few things around in.  Is there a nice way to get latex to output a list of forward references? (like, things in chapter 5 that reference a result in chapter 10) Regarding the `book`, `report`, and `article` document classes: what are the main differences?