How to add multiple images in background body
Can I have multiple background images using CSS?
Probability that a k digit number does not contain certain digits It's common in C++ to name member variables with some kind of prefix to denote the fact that they're member variables, rather than local variables or parameters. If you've come from an MFC background, you'll probably use m_foo. I've also seen myFoo occasionally.  C# (or possibly just .NET) seems to recommend using just an underscore, as in _foo. Is this allowed by the C++ standard? How do I stop the excel file being in use? I'm opening an Excel file and I'm getting the File in use pop-up that says it's locked for editing by me. However, I've not got it open on this computer (I think I had it open and my machine blue-screened). How do I go about fixing this?  Should specify, this is a file on a file share.  edit I'm not talking about if this is being used by another user on another machine, this is only accessible by me on this file share. The whole multi-continent aspect of A Song of Ice and Fire seems to be getting out of hand. Do the other continents suffer those long winters?  Can the Others harm the other continents?  In The Lord of the Rings there were other realms than Middle-earth, but Middle-earth was still all of humanity and dwarf population and hobbits.  Sure there are stories like Romeo and Juliet where the only thing that matters is whether those 2 are going have a chance to love.  But in these fantasy / sci-fi stories there's usually danger of world domination by evil.  It's not usually just one continent is going to be a terrible (or impossible) place to live but other civilizations will flourish. Dirac Delta or Dirac delta function? Batch export Photoshop layers to individual PNG files Space war, humans recreated, grown from plants with an alien female supervisor This was a small hardback book I read in the UK in the late eighties. No memory of the cover.  Some kind of space war and a long lived alien female escapes the conflict in her starship, her side had lost.  An evil enemy that she needs to trap so she gets (I think) human  DNA from space dust and sets up on a habitable planet. The story then gets like episodic and looks at the world every couple of generations while she hides out there.  Plants bud on the world and people pop out from big seedpods, the population listens out for babies crying and rescue them.  There are legends of the 'Earth mother’ who secretly guides them to become high tech.   In reality she is creating attractive food bait for the bad aliens.  I think an early human and her are attracted to each other and she (maybe) gives him long life or (maybe) uses reincarnation to keep seeing him.  Edit:- the name 'Rimstalker' has just now popped up in my brain! out file with multiple criteria in python? List of GUI Based Torrent clients Ubuntu GNOME 17.04: wi-fi not working -- mac address keeps changing? My Panda USB wi-fi adapter works just fine on 16.10, but when I try to connect to my wi-fi router in 17.04, GNOME network manager reports "Connection failed." I did some tinkering, and noticed that my MAC address for my wifi adapter, according to GNOME, is DIFFERENT every time I make it forget my wifi settings and try to reconnect. Any leads on a possible fix or work-around?   I'm running Ubuntu GNOME 17.04, kernel 4.10.0-19-generic, GNOME 3.24.0. How can I disable the Windows 8 charms bar? Can someone please tell me how to disable the annoying effect that pops up when you drag cursor to top- or bottom-right corners? Can't update because the word prox* is blocked When is $\phi(n)$ a prime number? I was thinking about this problem today. If $p$ divides $n$, then $p-1$ must divide $\phi(n)$. But $p-1$ is even for all primes greater than $2$, so must $\phi(n) = 2$ - the only even prime? I feel like this argument is shaky and not very rigorous! Is it true that all numbers of the form $\sqrt[b_1]{a_1}+\sqrt[b_2]{a_2}+\cdots+\sqrt[b_k]{a_k}$ are not integers, where $a_i,b_i$ are positive integers such that none of the $k$ terms is an integer? I think this must be a theorem somewhere, probably a fundamental theorem in number theory, but not sure what it would be called. I have parent folder "parent". Inside this folder I have subfolders, and a file named "names.txt". this file includes the names of these subfolders as follow:  Parent_folder folder1 folder2 folder3 folder4 . . . . names.txt   The content of the file "names.txt" is as follow:  folder1 folder2 folder3 folder4 . . .   Inside every folder I have images and I want to apply consecutively 10 scripts on every image ( every script must finish it is job inside every folder, then the second script must be run). These scripts have different names and they are exist in one folder. I set an environment by sourcing a file then I can call these scripts by its name from terminal .At the same time I want to apply this process on all the folders at once. i.e. when script #1 is running, I want it to be running on all the folders at the same time. When it is done and script #2 will start. I want it to start in all the folders at once and so on... In order to achieve this I wrote the following code:  #!/bin/bash path=PATH/TO/THE/PARENT/FOLDER for i in $(cat $path/names.txt); do { script#1 } &amp; { script#2 } &amp; . . .  done   This code is not working efficiently as all the commands are running at once. I want the commands to run on all the folders at once but consecutively.  What I am doing wrong? Accelerating electrons via microwaves In Synchrotrons I think they use microwaves to accelerate the electrons bundles that fly through-how does putting a microwave through a cavity accelerate an electron? I know that the Electric and Magnetic fields could and do have an effect on the electron, but if the radiation is moving parallel to the electron, wouldn't the force be perpendicular? Also, how exactly does the microwave radiation look in the vacuum chamber? Are the two ends constant nodes? I am currently facing a "performance problem" while using grep. I am trying to locate the occurrences of many (10,000+) keywords in many (think Linux kernel repository size) files. The objective is to generate a kind of index for each keyword:   keyword: my_keyword filepath 1 filepath 2 ------ keyword: my_keyword2 ...   Being fairly new to shell scripting, I have tried a few naive approaches:  while read LINE; do     echo "keyword: "$LINE &gt;&gt; $OUTPUT_FILE     grep -E -r --include='Makefile*' "($LINE)" . &gt;&gt; "$OUTPUT_FILE"     echo "-----" done &lt; $KEYWORD_FILE   This takes about 45 minutes to complete, with the expected results.  Note: all they keywords I search for are located in a file ("KEYWORD_FILE", so fixed before anything starts), and the files in which to search can be determined before the search starts. I tried to stored the list of files to search in before the search like that:  file_set=( $(find . -name "Kbuild*" -o -name "Makefile*") )   and then replace the grep call by  echo {$file_set[*]} | parallel -k -j+0 -n 1000 -m grep -H -l -w "\($LINE\)" &gt;&gt; "$OUTPUT_FILE"   It takes about an hour to complete&hellip;  Question: considering I can use whatever technique I want, provided it's sh compliant, how can this be done "faster" and/or more efficiently ?  Perhaps grep is not the tool to use, and my use of parallel is wrong&hellip; any ideas are welcome! "(" or "\left(" parentheses? What is the difference between ( and \left( in LaTeX? Sometimes, when the content is small, it does not seem to matter which pair I use.  What is the best practice when it comes to which parentheses use? Set Text Color for textView Android I've seen many boads with weird zig-zag shaped tracks just like the one below. Why are they designed like that?