I have seen 127.0.0.1 is local host address. But what is it and what is the differences between this and my local adapter like LAN  IP address or WLAN IP address. Is there any connection between this l27.0.0.1 and my LAN or WLAN Network card?
I found some articles related to this, but they were not sufficient for me. I want to know how the localhost works and why is it the same on many different machines?   How does the localhost block the access to the website when we use it in the host file to block the website?
I am using Adobe Illustrator CS6 to create small images (like icons) for my app so I need pixel precision.  How can I avoid X, Y, W and H properties to have decimals? Can I configure 0 decimals for this properties on my document?  If I use the textboxes with this properties it does right, it increases pixel by pixel, but when draggin with the mouse it uses up to 3 decimals. From what I understand, the frequency of light coming from the source moving towards an observer increases. From $ E=hv $ , this implies increase in energy of photon.  What really is confusing, is where does that extra energy come from? And also where is the energy is lost during opposite Doppler effect (red shift)? Why doesn't this violate the conservation of energy? of a monic polynomial $f \in \mathbb F\left[x\right]$ in $1$ variable $x$ over a field $\mathbb F$ plays an important role in understanding the structure of finite dimensional $\mathbb F[x]$-modules.  It is an important fact that the characteristic polynomial and the minimal polynomial of $C(f)$ are both equal to $f$. This can be seen quite easily by induction on the degree of $f$.  Does anyone know a different proof of this fact? I would love to see a graph theoretic proof or a non inductive algebraic proof, but I would be happy with anything that makes it seem like more than a coincidence! Implicit 'which is', 'which are' A new study has shown that millions of pieces of junk floating in  space could be a big hazard for satellites orbiting Earth.   Is there an implicit 'which are' in front of floating in space? Why is 'which are'  not written? Make flash drive bootable with MULTIPLE Windows Installers "The product key entered does not match any of the Windows image" I have a HP with Windows 7 installed. I want to do a clean installation of Windows 8 from a bootable DVD.   I purchased my Windows 8 32-bit core from the Microsoft store and I received my product key. I then burned the .ISO file to a blank DVD using imgburn. When I restart and change my BIOS to boot from internal CD/DVD and then boot from my internal DVD, I start the installation process.  After I pass the screen where I select the language and location, and click Install it stays there for a minute and then it says:     The product key entered does not match any of the Windows image   I did my research and learned that I need to add a PID.txt file to my source file containing the Windows 8 .ISO but the thing is: I do not know how to add files to the .ISO. The guide I researched is for a bootable USB and I am using a DVD. What is the "show desktop" keyboard shortcut? I just upgraded to 11.10 from 11.04. Previously the shortcut to show the desktop was Super +D (same as in Windows), But now it is not working. What is the new shortcut? Prove/Disprove that if two sets have the same power set then they are the same set I am really sure that if two sets have the same power set, then they are the same set. I just am wondering how does one exactly go about proving/showing this?  I'm usually wrong, so if anyone can show me an example where this fails, I'd like that too.  The homework just asks for true/false, but I'm wanting to show it if possible. My thoughts are that since the power set is by definition the set of all subsets of a set, if each of the two power sets are identical, we have an identity map between each set, thus it's indistinguishable which power set is a given set's power set. I hope that wasn't verbose. Since a set has only one power set, we can conclude they are in fact the same set. Why “which” returns none on some commands I can run? I used which to tell the location of a runnable file. For example, which pwd returns /bin/pwd. However, I found which alias or which compgen etc returns nothing.   What are commands like alias? Aren't they executable files on my Linux? I am using bash 4.3 on Ubuntu. I have an iPhone 6 128 GB which is not jailbroken. The current version of iOS on the phone is 8.1.3 and yesterday I wanted to update to iOS 8.2.  The download went through without any problem but while installing, it gave the error:     Unable to Install Update   An error occurred installing iOS 8.2   Tried installing after switching Off and ON and also tried Hard Reset (Holding Home button and On/off switch).  Same error displays every time.  Also the Touch ID has stopped working and I find that the Settings - Touch ID &amp; Passcode - iPhone Unlock is OFF.  When I try to switch it ON, the system displays the error     Failed   Unable to complete Touch ID setup. Please go back and try again.   Is anyone facing this problem?  I live in India. How many physical degrees of freedom does the $\mathrm{SU(N)}$ Yang-Mills theory have? The $\mathrm{U(1)}$ QED case has two physical degrees of freedom, which is easy to understand because the free electromagnetic field must be transverse to the direction of propagation. But what are the physical degrees of freedom the $\mathrm{SU(N)}$ Yang-Mills theory?   I believe that the $\mathrm{SU(N)}$ Y.M. theory has four degrees of freedom, and it is easy to see that by gauge fixing (such as the Lorentz condition or the Coulomb condition) that we can always remove one redundant degree of freedom. But then we still haven't completely fixed the redundant degrees of freedom. Thus my question is:     How many physical degrees and how many are redundant degrees of freedom does the Y.M. theory have?    I would be interested to understand how we can determine this mathematically, and also to understand what the physical intuition behind this is? I want to copy the data folders from a previous ubuntu(14.04) partition My hard drive is a mess and I want to reformat it and do a fresh install of 16.04. My problem is I only have access to the HDD via 16.04 on a USB stick and although I can navigate to the various folders, nothing I do allows me to copy to an external hard drive. The folders are not encrypted. I also have a small swap partition - I would like to preserve the data on that too if possible.  Here's a listing of the home directories on the drive:  ubuntu@ubuntu:/$ ls -l /media/*/*/home /media/ubuntu/0e228f65-dac7-435f-828b-1eb1a6c3f29a/home: total 4 drwxr-xr-x 46 1000 1000 4096 Dec 21  2015 simon  /media/ubuntu/db79a6d1-7c6c-4d8c-822b-ba6ccd1ddecd/home: total 4 drwxr-xr-x 27 1000 1000 4096 Apr 17  2014 simon  /media/ubuntu/ebe2a6ba-9cb5-4279-8352-5082b8dd4d5e/home: total 4 drwxr-xr-x 39 1000 1000 4096 Aug  3 14:21 simon Allow me to get notifications for new Meta posts, like mods do I'm currently helping out on . One of the most valuable things on new beta sites, especially private/early public betas, is Meta participation - see :  Treat Meta Questions Like Gold It’s not unusual for your meta site to receive significantly less traffic than the main site. The problems begin when you meta starts to get ignored by the community and ignored by the moderators. It is particularly disturbing when users reach out in meta and starts talking about improving the site or asking for help… only to be ignored; No follow-up, only deafening silence  Because of this, Diamond mods get a notification in their inbox for each new question on their Meta, helping ensure that each meta post is addressed. However, wouldn't it be great if Diamond mods weren't the only ones that could do this? The post does say that the community needs to be seeing these questions too. As an involved user, I would really like to be notified of these new questions - it would increase the good I could do the site. How about this?:  Of course, it would be opt-in, not opt-out, and per-site. A feature like this would greatly improve the good that enthusiastic site-builders can do for the site, and would, most likely, increase the overall chances of a site's success. A friend of mine misplaced his passport while staying in Jeju island. Normally I would advise him to just travel to Seoul, get an emergency passport from his embassy and fly back home without issues, but I know that Jeju island has a special immigration regime.   Are there any immigration checks on the way from Jeju island to Seoul? If not, can one travel that route without a passport? Separate long math text under sum symbol into different lines? I want to add a comma in the thousands place for a number.     String.Format()? How should artwork be setup for T-shirt printing? What does it mean to colour separate the artwork for T-Shirt printing? It is normally suggested to use Pantone colours for T-Shirt printing. Is it the Pantone Coated or the Pantone Uncoated? The Uncoated one has more subtle colours and we can't choose brighter shades if the design requires that. What is more appropriate for printing? Can we use gradients in T-Shirt printing or is it suggested to stick to flat colours only?   The reason for asking if gradients were ok was to use it as an option for this design:    I was considering it an option, as it will be difficult to colour separate since the textures are clip masked inside the lion. I'm using Rules 7.x-2.6 and the way it works has changed a bit since I last saw.  I have a rule as follows:  EVENT A node has been flagged, under "Report content"  CONDITIONS None  ACTIONS Send mail to [site:mail]   However, I'd like to, instead of sending directly to [site:mail], send an email to all users flagged with an "admin" role.   Now I know that I'll need to provide a loop do so, but my sticking point is generating the list of users to pass to the loop. So far, I have attempted to add a new action:   "Fetch entity by property" Entity type: User Property: User roles Value: admin   But this doesn't seem to give me what I want in data selection, when passing it to the loop. Can someone recommend what they would set here? I have a string that represents a non indented XML that I would like to pretty-print. For example:  &lt;root&gt;&lt;node/&gt;&lt;/root&gt;   should become:  &lt;root&gt;   &lt;node/&gt; &lt;/root&gt;   Syntax highlighting is not a requirement. To tackle the problem I first transform the XML to add carriage returns and white spaces and then use a  tag to output the XML. To add new lines and white spaces I wrote the following function:   function formatXml(xml) {     var formatted = '';     var reg = /(&gt;)(&lt;)(\/*)/g;     xml = xml.replace(reg, '$1\r\n$2$3');     var pad = 0;     jQuery.each(xml.split('\r\n'), function(index, node) {         var indent = 0;         if (node.match( /.+&lt;\/\w[^&gt;]*&gt;$/ )) {             indent = 0;         } else if (node.match( /^&lt;\/\w/ )) {             if (pad != 0) {                 pad -= 1;             }         } else if (node.match( /^&lt;\w[^&gt;]*[^\/]&gt;.*$/ )) {             indent = 1;         } else {             indent = 0;         }          var padding = '';         for (var i = 0; i &lt; pad; i++) {             padding += '  ';         }          formatted += padding + node + '\r\n';         pad += indent;     });      return formatted; }   I then call the function like this:  jQuery('pre.formatted-xml').text(formatXml('&lt;root&gt;&lt;node1/&gt;&lt;/root&gt;'));   This works perfectly fine for me but while I was writing the previous function I thought that there must be a better way. So my question is do you know of any better way given an XML string to pretty-print it in an html page? Any javascript frameworks and/or plugins that could do the job are welcome. My only requirement is this to be done on the client side. making a big summation sign How can I make a big summation sign?   ‎\begin{align}‎ ‎\cos x‎ ‎=‎ ‎‎\sum\limits‎_‎{n=0}^{‎\‎‎infty‎} ‎\frac{(ix)^{2n‎}}{(2n)!}‎‎ \end{align}‎   this is the code which I'm using for summation