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As it was suggested  I am using cat command to concatenate several .mp3 files into one .mp3 file. Imagine, I have following .mp3 files in the current folder: 001001.mp3 001002.mp3 001003.mp3 001004.mp3 001005.mp3  or, like this: 096001.mp3 096002.mp3 096003.mp3 096004.mp3  I need to concatenate these .mp3 files in there ascending sequence, i.e.  001001.mp3+001002.mp3+001003.mp3+etc. In order to join these .mp3 files into one I am executing following command in the current folder: cat *.mp3 &gt; final.mp3  I tested the final .mp3 file and it is what I am expected, but I need to be sure that above command picks files in there ascending sequence. Can I be sure that above command always concatenates files in the ascending sequence? Thank you Sir! How can I make realistic looking potions as handouts I'd like to give my group some realistic looking potions as handouts.  Does anyone have tips on how I could make these look awesome? Stop the Ubuntu updater from nagging about Firefox English Language pack even after uninstalling Firefox I have run sudo apt purge firefox, and I have gone through all of the /.config files, etc., and Software Updater is still asking me daily if I want to install the &quot;English Language Pack for Firefox&quot;. I don't have Firefox installed. How can I stop the updater from asking to update something on a program that doesn't exist? Output of dpkg -l | grep firefox: ii  firefox-locale-en                          88.0+build2-0ubuntu0.18.04.2        amd64        English language pack for Firefox I just notice it now as I am new to Illustrator.  When I am in RGB mode, blending transparency seems to be easier as mode such as Screen, Multiply or Overlay looks good naturally.  If I switch the document mode to CMYK then the image is getting messed up.  I'd like to know, if CMYK is not ideal for blending options? reference variable In some text it is given that we can't assign constant values to a reference variable. When I executed such a program I could do it. Is there any condition we can't assign a constant value to a reference variable? How to make 'python' program command execute Python 3? Is there an equivalent of computation of physical processes in nature? I was watching a waterfall in the Austrian Alps. There were thousands of water droplets falling down, splattering on the stones below. I thought - how does nature find out so quickly where each droplet of water should go? To find out what happens to a falling droplet of water, one can use the laws of motion and calculate the trajectory. To calculate, one needs some amount of time, some machine (the brain, computer) and some energy to feed the machine. Does it make sense to ask what is the equivalent of this computation in nature? How does nature find out so quickly how things should move? More generally, to find out how anything should happen? Where is the &quot;calculation&quot; in nature? There's no room or energy for a machine in the particles that make up things. How do you make a torus 'telescope' open? So I have a torus, and I need it to "telescope" open -- kind of like Pacman's death animation, but with a torus instead of a sphere.  I'm very new to 3D modeling/animating so I really have no clue how to tackle this problem.  Any advice to help me get pointed in the right direction would be most appreciated :) Mac App Store: Downloads just don't start (Mojave) I want to download apps in the Mac App Store and the apps won't start to download. As you can see in the pictures below, the spinner starts spinning but nothing gets downloaded, the download simply doesn't start. I am logged in with my account. I tried logging out of the App Store and logging in again, restarting the Mac etc, nothing helped.  This is a relatively fresh installation of Mojave 10.14. Before with High Sierra 10.13 everything worked fine. It's a Late 2013 MacBook Pro 13". Installations are allowed from App Store and identified developers.   Some screenshots from Console output below. What does the "@" symbol do in SQL? I was browsing through the questions and noticed this:  SELECT prodid, issue FROM Sales  WHERE custid = @custid  AND datesold = SELECT MAX(datesold)               FROM Sales s               WHERE s.prodid = Sales.prodid                   AND s.issue = Sales.issue                   AND s.custid = @custid   I was wondering what the "@" does in front of custID?  Is it just a way of referencing the custID from the table being selected? Propose Newbie-Overflow site or section Because the perl section is looking like that right now. I believe that Stack Overflow is going out of it's charter in becoming a newbie FAQ when as far as the original reasoning it was meant to be something along the lines of an expert site.   is a good example of what I mean in Perl. It probably could be closed because it's a duplicate, or some other reason.   I would also like to indicate that I don't hold back answering newbie questions. It's just when I think of an obscure "stack overflow" error that's beating you some 3 am close to deadline, that's not "Howcum Perl print ..." and follows with something that causes a vast majority of Perl programmers to say oops, because they know exactly what's going on.   So the proposal is   A new site. "Move to Newbieville" A new "section" A new status somewhat similar to Closed ("Newbied") but still can be updated all the same as an open question.   I'm not against giving some newbies an assist, but I feel a FAQ for rank newbieism is not something that SO started out to be, based on the original concept of a Expert Site.   Including comment to Gnoupi:   I said nothing about making newbies unwelcome. Like I said. I answer them--heck, I think I've even answer homework questions. I've answered on the vague impressions that I can glean from posts that have 4 close votes. It can even lead to avoiding downvoting or yelling at newbies by more established curmudgeons if there is a special action you can do to gently inform newbies that this is a real newbie question.  However, you have to know that to some people newbies are already unwelcome. There is a site ethic, but the individual is also going to decide how much they welcome newbies. And people do post RTFM answers already.   Anyway, I'm one vote away from a peer pressure badge it seems. (Nope, nailed it.)    EDIT  For somebody jumping to the conclusion that I'm hostile to newbies:  just earlier How to get the current date/time in Java Logic gate - What will be the second input of each gate? Full:    Cropped   :    In the second image (cropped) which is the same as the first (full) image... why the 1st Gate outputs "0"? Would someone explain wheel sizes.  If I am not mistaken, the wheels on my Trek 520 touring bike are 700C. There are no markings, and of course, no documentation of any kind. I assume 700 means 700mm, so 700 / 25.4 = 27.56 inches.  If I measure the rim however, its diameter is approximately 25.1 inches.  If I buy Continental tires, the size is 28 inch, but I have to buy 27 inch Bontrager tubes.  To make matters worse, per this link, tires come in sizes of 26, 27, and 28 inch, and size 700.     How can I determine my wheel size, and are these various sizes interchangable. Also, is the 'C' suffix important, and what does it mean?  Of course the tires are marked, but I am under the impression (per the dealers comments) that Continental marks their tires differently than everyone else. Also, the tire markings don't help for ordering a new wheel.   With so many tire sizes available, how can I know if I am using the correct size.  After reading the various answers here, I should explain that my confusion on this matter stemmed from the fact that I used to work as an auto mechanic. In the auto industry, car tires are based on wheel size, 13", 14", 15" etc, and there is no possible way to mount a 15" tire on a 13" rim for example.  So when I saw all these different tire sizes, I assumed they all required a different wheel size, but in fact, there is essentially just one wheel diameter for my type of bike, which they refer to as 700C, which is actually 622mm.   I also initially assumed that the C referred to the wheel's width, but that isn't true either. The C is apparently just antiquated terminology.  So at least in theory, I can mount a 26", 27" 28" or 29" tire on my 700C (622mm) rim. I just need to verify the width of the tire is suitable my wheel width, which is what Sheldon Brown's article explains.  Also, I measured my Continental tires, which are marked as 28 inch. They actually measure 27 inches (fully inflated), which must be why my dealer calls their sizing non standard. I recently learned that I have developed a consistent, but entirely wrong approach to punctuating direct speech in fiction. I am in the unenviable position of trying to relearn.  Previously I wrote such things as:     "I'm done." She said.   when the quoted speech was definitely, absolutely the end of a sentence. So now I know I need.     "I'm done," she said.   This follows the rule that a period is only allowed when the end of the spoken sentence is also the end of the sentence in the narrative. For example:     "I'm done." She slammed the door on the way out.   So, it now looks odd to me when there are multiple sentences in the speech:     "I can't take her. I'm done," she said.   Can you reassure me that is correct, or give the correct form? Please don't suggest rewriting the sentence to put 'she said' in the middle - I'm aware of that: I'm specifically asking about the punctuation rules.  The other odd case is speech ending with an ellipsis. Do sentence terminating ellipses (four periods normally) become:     "I can't take her. You know, ...," she said, nodding towards Jane.   If so, are non-terminating ellipses dealt with the same way?     "I can't take ...," she nodded towards Jane, "any more!"   or can non-terminating ellipses be used unadorned?     "I can't take ..." she nodded towards Jane, "any more!"   I'd be very grateful if you could point me at references as well as answers. For the record I am a British writer writing for both British and US publication, so any variation is also interesting to me! How to zoom in/out an UIImage object when user pinches screen? How to copy some, but not all files? So, you can use the * as a wild card for all files when using cp within context of a directory.  Is there a way to copy all files except x file? Accessing Reduce from DSolve How to get RGB values from UIColor? I'm creating a color object using the following code.  curView.backgroundColor = [[UIColor alloc] initWithHue:229 saturation:40 brightness:75 alpha:1];   How can I retrieve RGB values from the created color object? I have installed Ubuntu 13.04 on my desktop (runs like a charm). Then I used Crouton to install Ubuntu 12. 04 on my chromebook samsung (ARM). It also works quite well.  Here comes my question. Can we have a true Ubuntu (preferably 13.04) on my ARM chromebook?  It seems that the Crouton/Ubuntu is not 100% the real thing.  The best option would be to have the full Ubuntu 13.04 and remove the Chrome OS.