Probability that an $m$ digit number does not contain $0$, $5$, $6$ nor $9$
Probability that a k digit number does not contain certain digits
I keep reading about  ('PPAs') and people answer questions with a link to a PPA. What's the best way to use these?     There are multiple valid answers for this question spanning over several versions of Ubuntu. For your convenience, an index of each is below. I'm trying to install Wifite from , but I can't install cowpatty.  See below:  root@vitor-hp:~# apt-get install cowpatty Reading package lists ... ready Building dependency tree Reading state information ... ready E: Could not find package cowpatty root@vitor-hp:~#    Translated from Portuguese  I use Ubuntu 13.10 64-bit. How to delete blank lines starting from line 5 I have this:  sed -i '/^$/d' temp_spec.rb   which is stripping blank lines and works well.  How can I make it only do this for lines 5-999 (or ideally 5 to end-of-file).  I tried:  sed -n5,999 -i '/^$/d' temp_spec.rb sed '5,999!d/^$/d' temp_spec.rb   but neither worked (no errors). At what point does a caster define the target of a spell? The new School of Invention tradition for Wizards () while still in playtesting (and indeed a bit silly in my opinion, more of a "chaos wizard"), got me thinking about its reckless casting ability. This allows the caster to cast magic they do not have prepared and get a random result. The random spells have different targeting criteria (Wall of Stone, Fireball, Feign Death , Mass Cure Wounds) and so it is not possible to decide the target of the spell until it has been cast, as you don't know what you are going to get until it is cast.  This suggests that the designer of the subclass has made the assumption that you don't actually target until you have cast the spell and release it, which makes sense from one point of view, strongly supported by the way a prepared action casting works, PHB p.193 where you cast the spell and hold the energy until the condition is met for the readied action at which point you target the spell.  While the Unearthed Arcana is not RAW or finalized and released, my question is not about this subclass, but about the official rules as a whole.  Is there was any direct RAW, or other supporting or opposing RAW, that states at what point a caster defines the target of a spell?  As a sub-question: are there any circumstances where it actually matters, other than the already defined Readied Action spell casting, in the official rules? How do I kill mobs using /kill without them dropping loot? I have a spawn area I am hoping to make a safe haven, so I have a command block on a clock that kills each hostile mob type. This works to keep the place free of any hostile mobs, however every night I see rotten flesh, bones, arrows, and string everywhere.  I would like to add something to my command blocks so that they are killed without dropping loot. How can I accomplish this?  Note that I want mobs to drop loot generally elsewhere in the world, so /gamerule doMobLoot false will not do the trick for me. I'm hoping for a command that only applies to the mobs killed by the command block, and not anything else. I need to get rid of the GNOME Desktop Environment which has been installed by default when I updated my pc from 15.10 to 16.04.  After a while, I found myself not only with GNOME DE, but also with Cinnamon alongside (in the login screen, I could choose at least five or six DE!)  Now I am using Unity, and I'm happy with that, and I successfully uninstalled Cinnamon, but now I'm afraid that after uninstalling GNOME I will mess up the Unity DE, since I see many packages running in unity with the packagename starting with gnome-... Would someone mind to help me? Thx in advance What characters/symbols are allowed within the CSS class selectors? I know that the following characters are invalid, but what characters are valid?  ~ ! @ $ % ^ &amp; * ( ) + = , . / ' ; : " ? &gt; &lt; [ ] \ { } | ` # Is it possible to hide curves' guides in edit mode? Why is the direction of cross products of two vectors perpendicular to the plane? Why is the direction of cross products of two vectors perpendicular to the plane? How is that possible? The use of "real" in the following cases Possible Duplicate:             If you listen real close...      Can you swing by real quick...   Sentences like the above two are what I often hear in daily life. If I didn't hear them in the real world, I would probably be more ready to say "If you listen really close..." and "Can you swing by really quick...".  Is real being used as an adjective in this scenario? If so, is the usage of adj.+ adj. a common practice in English language? Several responses to a question  suggested I try Opera kiosk mode, so I decided to download it and give it a try. Once the download had completed and the disk image was being verified, Safari hung for over a minute and there were periods where Safari used a very high %CPU:    In Mac OS X 10.5, I was accustomed to seeing Safari freeze, but it never used up more than 200% CPU (2 cores x 100%). Is this a bug in Activity Monitor? Or does this mean that %CPU is now more akin to ? Selenium 2: Open link in new tab and close tabs Can Mystique create objects? Proving Invertibility and Eigenvalues If matrix $A$ is an $n\times n$ matrix such that $A^2 -A -2I=0$.  How can I show that $A$ is invertible and that $A^{-1} = \frac12(A-I)$? Also, how do I show that one of the eigenvalues of $A$ is $2$ or $ -1$? I appreciate any help on this question. Is there a quick way to lock my Mac? On Windows you can hit the keys Windows+L to lock your computer if you step away.  I don't want to have to remember if sleep currently asks for a password, if there is a time out where my screen isn't locked during a short period. Even with Lion supporting resume of many apps, I don't want to log out.   I do want to be sure data is secure when stepping out for lunch or a smoke break. What is the name for the grammatical device of putting "not" after a verb to negate it? pgfplots from file: search path, looking for \graphicspath equivalent When should I use the new keyword in C++? Command prompt as SYSTEM user (Windows 7) How can I get a command prompt as the SYSTEM user on Windows&nbsp;7?  Context: I'm testing a computer startup script, and I need to figure out the behavior of a command when run as SYSTEM rather than my user account.  I've seen ways to do this with at and psexec, but those methods only appear to work on Windows&nbsp;XP or Windows&nbsp;Vista.  I'm using Windows&nbsp;7 Pro SP1. What is the rule of thumb for mixing doughs? Without delving too deeply into specialty doughs, but addressing more than just  and , what concerns can I evaluate when calculating the technique for approaching a dough?  For instance, some recipes say not to mix too much, others would imply that beating every bit of air out of the dough is the best thing for it. What I am looking for is a set of criteria, maybe a flowchart, that outlines how to deal with having a well-reasoned technique (as opposed to just following a recipe).  Crumble, cream, or melt the fat first? Paddle or hook? Beat, fold or whisk? Knead once and rest or knead three times and throw? I would assume that to some extent getting air in or out, activating and mixing ingredients, distributing fats more or less evenly, and so forth play a factor in any decision. However, I have no idea what those different things do, or the food science behind them. What general principles would help me understand what each factor does, so that I can have more confidence when staring down the ingredients, whether for some cookies or pizza crusts or muffins?