How to insert an unbreakable space when LaTeX3 syntax is turned on
How do I insert a tie (~, non-breaking space, tilde) under expl3 syntax?
How can you detect if users have created sock puppet accounts? How many users have created more than one profile on SO to vote themselves on their other original profile? There are some benefits when you have more reputation and sometimes you don't want a single -1 vote on your question or answer. In this case you may have an extra account to convert that -1 vote into 0 vote and  upvote for each of your questions and answers to gain reputation. I think it is not a good thing to do as a good developer.  Is there any way to recognize this situation? I think there should be some stats in each user's profile about how many votes are posted by each user on him/her or something like that.  So how many users have more than one profile? How to handle this situation? I have not created one yet but............ I don't think so :) Delete files except n files with the "bigger" name? Do dual American and Mexican citizens need passports to travel between the US and Mexico? I have 2 children that were born in Mexico. They have a birth certificate abroad. So this is dual citizenship. Do they need passports?  My kids were born in Durango, Mexico. I am American. Their father is Mexican. They were both given birth certificates abroad. They are now 16 and 14. They want to go visit grandparents and aunts and uncles in Mexico.  Will they need to get a passport to enter Mexico?  Will they need it to fly? Show that $1^{p-1} + 2^{p-1} +\ldots + (p-1)^{p-1} \equiv -1 \mod p$ Show that    $$1^{p-1} + 2^{p-1} +\ldots + (p-1)^{p-1} \equiv -1 \mod p$$   So, I use Fermat's little theorem, that is if $p$ does not divide $a$, then $a^{p-1}$ is congruent to $1$ (mod $p$). But I'm still confused. If $1^{p-1}$ is congruent to $1$ (mod $p$), $2^{p-1}$ is congruent to $1$ (mod $p$), and $p$ does not divide $p-1$, so $(p-1)^{p-1}$ is congruent to $1$ (mod $p$). How does that equal $-1$ (mod $p$)? Changing parameter values according to other parameter choice in Processing script using QGIS 3? I couldn't find anything about this problem.  Suppose to have the first parameters in a Processing script defined as an Enum:     self.addParameter(         QgsProcessingParameterEnum(             self.CHOICE,             self.tr('Choose the parameter'),             ['param1', 'param2']         ) )   While the second one as a number:  self.addParameter(     QgsProcessingParameterNumber(         name=self.VALUE,         description=self.tr('My value'),         type=QgsProcessingParameterNumber.Double,         defaultValue=40,         optional=False,         minValue=0,         maxValue=100     ) )   Is it possible to change the minValue, maxValue, description, ecc.. of the second parameter depending on the first or second choice of the first parameter already in the GUI?  e.g. if the user choose param1 then the second parameter should become:  self.addParameter(     QgsProcessingParameterNumber(         name=self.VALUE,         description=self.tr('My value'),         type=QgsProcessingParameterNumber.Double,         defaultValue=40,         optional=False,         minValue=0,         maxValue=100     ) )   while if he choose param2 it should became:  self.addParameter(     QgsProcessingParameterNumber(         name=self.VALUE,         description=self.tr('My AWESOME value'),         type=QgsProcessingParameterNumber.Double,         defaultValue=0,         optional=False,         minValue=50,         maxValue=500     ) ) Why is everybody so concerned about etc/passwd? Here is the content of my vagrant machine of this particular file:  root:x:0:0:root:/root:/bin/bash daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin bin:x:2:2:bin:/bin:/usr/sbin/nologin sys:x:3:3:sys:/dev:/usr/sbin/nologin sync:x:4:65534:sync:/bin:/bin/sync games:x:5:60:games:/usr/games:/usr/sbin/nologin man:x:6:12:man:/var/cache/man:/usr/sbin/nologin lp:x:7:7:lp:/var/spool/lpd:/usr/sbin/nologin mail:x:8:8:mail:/var/mail:/usr/sbin/nologin news:x:9:9:news:/var/spool/news:/usr/sbin/nologin uucp:x:10:10:uucp:/var/spool/uucp:/usr/sbin/nologin proxy:x:13:13:proxy:/bin:/usr/sbin/nologin www-data:x:33:33:www-data:/var/www:/usr/sbin/nologin backup:x:34:34:backup:/var/backups:/usr/sbin/nologin list:x:38:38:Mailing List Manager:/var/list:/usr/sbin/nologin irc:x:39:39:ircd:/var/run/ircd:/usr/sbin/nologin gnats:x:41:41:Gnats Bug-Reporting System (admin):/var/lib/gnats:/us$ nobody:x:65534:65534:nobody:/nonexistent:/usr/sbin/nologin syslog:x:100:103::/home/syslog:/bin/false   Could anybody explain me why it is bad if some evil guy could get this file of my production server? I have a query where I chain two columns. Why does the alias not work in the GROUP BY clause but in ORDER BY clause, it does work? How can I write the select correctly?  SELECT   KOS_VER_ID        AS "Vertrag"   , WHR_ISO_3_CODE  AS "Waehrung"   , KOS_KOA_ST_KZN || '  -  ' || ST_LANGBEZ_EN as "Kostenart"   , SUM (KOS_BETRAG) AS "Summe pro KOA" FROM   KOSTEN   , WAEHRUNG   , SCHLUESSELTABELLE WHERE    KOSTEN.KOS_VERHI_WHR_ID = WAEHRUNG.WHR_ISO_ID   AND KOSTEN.KOS_KOA_ST_KZN = SCHLUESSELTABELLE.ST_ID   AND KOS_VER_ID in (2509, 2510, 2511) GROUP BY   KOS_VER_ID   , WHR_ISO_3_CODE   , KOS_KOA_ST_KZN || '  -  ' || ST_LANGBEZ_EN ORDER BY   "Vertrag"   , "Kostenart" ; I have reviewed this:   but it does not answer my question. The suggested fixes in this question is to set up FB, IG, and other social media pages. We have had these for months. We have 576 Instagram followers, 293 followers on Facebook, 17,425 views on Vimeo, Youtube, Pinterest and LinkedIn presence. Here is the response in a YouTube search:  Let's be clear. If you search for my company name and product name YT changes the spelling to something that doesn't exist and suggests a video with no matching result terms (using either spelling) disparaging OTHER luxury handbags, while insinuating it is referring to my handbags. When a user searches for our business, , Google and Youtube changes the spelling to Aslan Vaughn and displays these results:  For the first few months it just seemed like it was taking some time to percolate, but over 7 months we have had 17,500 unique visitors and nearly 90 backlinks.  The only results for Aslan Vaugn is the birth announcement of the second child of a musician in New Jersey. It is a Facebook post and has 14 likes. Google is favoring a spelling that has only two results with 14+ views over dozens of links and tens of thousands of views. How is this possible? An FB post with 14 likes is that much more popular than a business with 17,500 unique visitors (despite the Google obfuscation)? Is my company on some list? On other search engines my company covers the first few pages in results. Through Google, you cannot find our company no matter how many pages in you go. Unless you search for the term in quotes, . In which case we cover the first few pages here as well: How to capture workload from production to replay on test? I want to perform performance testing on my test server.  How can I capture workload from production and replay on my test server?   Basically I'm looking for detailed steps so that I can replay the workload from production to my test environment. Newtonian mechanics: massless particles `sudo echo "bla" >> /etc/sysctl.conf` permission denied Disclaimer: I'm pretty novice at sysadmin stuff.  I'm trying to set up port forwarding in an AWS EC2 instance, this has to be done in the command-line because I don't want to go in and edit anything, it has to be automatic (it's part of a build process).   sudo echo "net.ipv4.ip_forward = 1" &gt;&gt; /etc/sysctl.conf      Permission denied   The weird thing is I've been (successfully) using sudo for pretty much every command that required su privileges. If I do sudo su before the command (trying it out by hand in an ssh session), then it works.  Reasons behind this? Possible solutions that don't involve sudo su or manual edits? How to calculate the limit of $\frac{a_n}{n^2}$ for the sequence $a_{n+1}=a_n+\frac{2 a_{n-1}}{n+1}$? Assume $\{a_n\}$is a sequence which  satisfies the following recursion formula: $$a_{n+1}=a_n+\frac{2a_{n-1}}{n+1}~(n\geqslant 1).$$ and $a_0=\pi,a_1=\pi^2 $. How to compute $\displaystyle\lim_{n\to \infty}\frac{a_n}{n^2}$? Thanks to the internet, graphic design and programming are becoming increasingly overlapping fields.   As a programmer, I constantly find myself needing basic knowledge of Graphic Design, but have trouble locating thorough yet concise graphic design learning resources, and instead usually find bits and pieces of knowledge applicable to the task at hand.  Can you guys offer some tips or recommend some good books, tutorials, blogs, and websites which provide a beginner level overview of web design that have been, in your experience, effective and high quality learning materials. I'm not looking for tips on how to use image editing tools, but assuming a basic grasp of those, which resources and advice will best help a new designer create professional looking designs? Modelling population with $\frac{dP}{dt}=P(\beta - \delta P)$ Simple prime number generator in Python What happens to the temperature when an ideal gas is compressed? I am rather confused about this. I know from Charles' law that under constant pressure, the volume of a gas is directly proportional to its absolute temperature i.e.  $$\frac{V_1}{T_1} = \frac{V_2}{T_2}$$  Thus accordingly, during compression, temperature of the gas would decrease. But in Lectures of physics ,vol 1 by Feynman, it is written:     Suppose that the piston moves inward, so that the atoms are slowly compressed into a smaller space. What happens when an atom hits the moving piston? Evidently it picks up speed from the collision. [...] So the atoms are "hotter" when they come away from the piston than they were before they struck it. Therefore all the atoms which are in the vessel will have picked up speed. This means that when we compress a gas slowly, the temperature of the gas increases.   (Constant pressure?) So, this is contrary to Charles' law. Why does this happen? Who is right? Or are they both correct? I am confused. Help. I want to click on file to inherit the name for the file being saved. I can't read file names in the dialog box because the color is too faint. This is the same question as   That question does not have an answer but I don't have enough points to interact there so I have to post a new question.    Edited to add screen shots I tried to calibrate the monitor which no effect and did not change the readability of "unavailable" file names. I have added screenshots of previous operating systems to compare: Please tell me how Mojave is not to blame here: Suppose I have a 6 GB page file on an SSD and another 6 GB page file on a traditional mechanical 5400rpm SATA drive.  Does Windows take into account the difference in the performance characteristics between the two drives when deciding which page file to use?  If it matters, I'm asking about Windows 7 and higher.  I reviewed this  but it doesn't appear to factor in the case of dissimilar storage speeds. Is it ok to ask to explain a certain piece of code on SO? Is it OK to ask on SO for help in explaining someone else's working piece of code, from Open Source projects or library examples etc.? Or does this belong somewhere else? Short circuit evaluation and side effects