Bash one liner not looping
Using while loop to ssh to multiple servers
Why doesn't mass of bob affect time period? The gravitation formula says $$F = \frac{G m_1 m_2}{r^2} \, ,$$ so if the mass of a bob increases then the torque on it should also increase because the force increased. So, it should go faster and thus the oscillation period should be decrease.  My physics book says that period is only affected by effective length and $g$. Why doesn't mass of bob affect the period? What does "yield break;" do in C#? I have seen this syntax in MSDN: , but I don't know what it does.  Does anyone know? ensurepip is disabled in Debian/Ubuntu for the system python I am trying to make a virtual environment for the development of my Django application. The commando's which I am using:   vagrant@vagrant:/var/www/djangogirls$ python3 -m venv myvenv The virtual environment was not created successfully because ensurepip is not available.  On Debian/Ubuntu systems, you need to install the python3-venv package using the following command.      apt-get install python3-venv  You may need to use sudo with that command.  After installing the python3-venv package, recreate your virtual environment.  Failing command: ['/var/www/djangogirls/myvenv/bin/python3', '-Im', 'ensurepip', '--upgrade', '--default-pip']   vagrant@vagrant:/var/www/djangogirls$ sudo apt-get install python3-venv Reading package lists... Done Building dependency tree        Reading state information... Done python3-venv is already the newest version (3.5.1-3). The following packages were automatically installed and are no longer required:   javascript-common libjs-jquery libjs-sphinxdoc libjs-underscore python-pbr python-pkg-resources   python-six python-stevedore python3-virtualenv virtualenv virtualenv-clone Use 'sudo apt autoremove' to remove them. 0 upgraded, 0 newly installed, 0 to remove and 108 not upgraded.  vagrant@vagrant:/var/www/djangogirls$ python3 -m ensurepip ensurepip is disabled in Debian/Ubuntu for the system python.  Python modules for the system python are usually handled by dpkg and apt-get.      apt-get install python-&lt;module name&gt;  Install the python-pip package to use pip itself.  Using pip together with the system python might have unexpected results for any system installed module, so use it on your own risk, or make sure to only use it in virtual environments.   vagrant@vagrant:/var/www/djangogirls$ rm -r myvenv/   vagrant@vagrant:/var/www/djangogirls$ python3 -m venv myvenv The virtual environment was not created successfully because ensurepip is not available.  On Debian/Ubuntu systems, you need to install the python3-venv package using the following command.      apt-get install python3-venv  You may need to use sudo with that command.  After installing the python3-venv package, recreate your virtual environment.  Failing command: ['/var/www/djangogirls/myvenv/bin/python3', '-Im', 'ensurepip', '--upgrade', '--default-pip']   As you can see, I am trying to make a myvenv, which cannot be created due to the python3-venv missing. I have already installed this, but the ensure pip is missing. After searching it seems that the system (Ubuntu 16.04) discourages the usage of the package. Could someone help me work around this problem? Do not hide VLQ flag option from users who already flagged and may wish to retract 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 ? Many econometrics textbooks (e.g. Wooldridge, "Econometric analysis...") simply write something similar to: "If the population model is $y = xB + u$ and (1) $\text{Cov}(X,U) = 0$; (2) $X'X$ is full rank, then OLS consistently estimate parameters $B$". I've worked out the math behind consistency but I'm a bit lost in interpreting the meaning.  We're talking about consistent estimation, but estimation of what? Please tell me if the following points are correct:   If we have random sample $X,Y$ and $X'X$ is invertible, then we can always define Best Linear Predictor of $y$ given $x$. And then OLS always consistently estimates coefficients of Best Linear Predictor (because in BLP we have $\text{Cov}(u,x)=0$ from the definition). Bottom line: we can always interpret OLS estimates as coefficients of BLP The only question is whether BLP corresponds to conditional expectation $\text{E}(y|x)$. If it does (for which we need $\text{E}(u|x) = 0$), then we can interpret OLS estimates as partial effects.   What is wrong with this or what am I missing? I don't get the point of stating the assumption of $\text{Cov}(u,x) = 0$, if this assumption is by definition fulfilled in case of Best Linear Predictor. And if we want to give structural interpretation to BLP coefficients (partial effects) we need stronger assumption of $\text{E}(u|x) = 0$ anyway. Is there any other interpretation we may have with zero covariance? I know that \: in LaTeX produces a space when rendered.  Are there any alternatives, because my LaTeX renderer doesn't support \: (it renders it as text), and there is no help / FAQ that I can find. How to prove that homomorphism from field to ring is injective or zero? Possible Duplicate:          $f:K\rightarrow R$ is a homomorphism from field to ring. To prove is that it is injective or zero. Set the location in iPhone Simulator Starting iPhone app development in Linux? I've heard that you need to get a Mac if you want to develop iPhone apps. Is this true?   Is it possible to develop iPhone apps using Linux? If yes, what do I need and where do I download the necessary tools? If $A=AB-BA$, is $A$ nilpotent? Let matrix $A_{n\times n}$, be such that there exists a matrix $B$ for which $$AB-BA=A$$  Prove or disprove that there exists $m\in \mathbb N^{+}$such  $$A^m=0,$$  I know $$tr(A)=tr(AB)-tr(BA)=0$$ then I can't.Thank you How do I find a recursion formula to solve the following question:  In how many sequences of length $n$, with elements from $\{{0,1,2,3,4}\}$, the difference between every 2 adjacent elements is $1$ or $-1$?  I've been trying to solve the problem for the last 5 hours maybe, I'm sure that I'm missing something..   This is a problem in combinatorics, and the solution must be by finding a recursion formula for the problem.   best solution I've come so far is that if we say that $a_n$ is the solution to the question, so let's count how many sequences of size $n-1$ there are that meet the requirement, and we complete the first element to make it a sequence of $n$ elements. so for $n-1$ there $a_{n-1}$ sequences, and for each sequence we have $2$ options to choose the first element (one option is to take a plus $1$ number from the number that start the $n-1$ sequence, and the other option to to take a minus $1$ number from the number that start the $n-1$ sequence), only problem as you figured out is that if the $n-1$ sequnce starts with $0$ or $4$ there is only $1$ option left for the first element in the sequnce.. so $a_n=2a_{n-1}$ won't work.  I think that the solution may involve using $2$ or maybe $3$ recursion formulas.  Hope I was clear enough. $\lim_{n→∞} f(n+x)=0$ results in $ \lim_{x→∞} f(x)=0$ $f\colon [0,\infty) \to \mathbb{R}$ is uniformly continuous.  If $\lim_{n\to \infty}f(n+x)=0$ where $x\in [0,1]$, then $\lim_{x\to\infty} f(x)=0$.  every my trying to solve this is wrong :(  how can i prove this?  and if $f$ is just continuous, what happens to the results Let $\mathbf{Y}$ be a random vector. Are $k$th moments of $\mathbf{Y}$ considered? I am self-learning on linear model theory right now, and one thing I find surprising is that although $\mathbb{E}[\mathbf{Y}]$ is defined for a random vector $\mathbf{Y} = \begin{bmatrix} y_1 \\ y_2 \\ \vdots \\ y_n\end{bmatrix}$, there is no mention of further moments besides the covariance matrix.  Google searching hasn't turned up much. Are $k$th (raw) moments of $\mathbf{Y}$ considered, or is there a different idea I don't know about?  I am learning from the text  (the TOC starts in p. 17 of the linked file). By "considered," what I mean is is there such a thing as $\mathbb{E}\left[\mathbf{Y}^k\right]$, and if so, how would such a concept be defined? The book I have only covers the first raw moment, and I find it a bit strange that there is no mention of how to define $\mathbb{E}\left[\mathbf{Y}^k\right]$ given my experience in univariate probability, nor do I have the expertise to define it.  Furthermore, if $\mathbb{E}\left[\mathbf{Y}^k\right]$ isn't defined, is there perhaps a related concept that I don't know about that is used instead? Separator between command list and } The Bash Manual says   { list; }        Placing a list of commands between curly braces causes the list to be executed in the current shell context. No subshell is   created. The semicolon (or newline) following list is required.      The braces are reserved words, so they must be separated from the list   by blanks or other shell metacharacters.       The parentheses are operators, and are recognized as separate tokens   by the shell even if they are not separated from the list by   whitespace.   If I remove the semicolon, like this:  $ { date } &gt;    Why does it expect stdin input? A metacharacter is a character that separates words.  The semicolon and whitespace are both "shell metacharacters". Why can't whitespace separate words date and }? Why do we need a semicolon instead of a whitespace for separating the words? How do I add VBA in MS Office? I've seen posts showing answers which use VBA () code/macros, however, I've also noted additional comments afterwards about how to use the VBA (how to implement and execute it). I'm hoping this will help just to get the code executed.   So, my question is:  I have some VBA code. How do I add VBA to my MS Excel or Word or Outlook project? What is scientific mind? Alka Seltzer Model: formulas/models requested This evening I became fascinated with how my Alka Seltzer tablet disintegrates over time within a small portion of Diet Lipton Citrus Ice Tea. I used a nearly frozen cup; tall, as one might request in a middle-class restaurant.  It is interesting to notice that the Alka Seltzer tablet attempts to float to the top of the glass; but it just cant quite make it, e.g., it keeps bobbing up and down and finally it becomes complete residue.  What are the formulas for this, completely? What might the mathematical model look like from start to finish? My first identifications include, but certainly not limited to: measuring the cup, the milligrams deposited into the cup and of course a the makings of a typical tablet of Alka Seltzer excluding room temperature? So here is what i want to pull : mmcblk0 whith it's size 15.7 GB.  C:\adb&gt;adb shell shell@android:/ $ su su shell@android:/ # fdisk -l /dev/block/mmcblk0 fdisk -l /dev/block/mmcblk0  Disk /dev/block/mmcblk0: 15.7 GB, 15758000128 bytes 1 heads, 16 sectors/track, 1923584 cylinders Units = cylinders of 16 * 512 = 8192 bytes   This is what I tried:  C:\adb&gt;adb shell su busybox cat /dev/block/mmcblk0 &gt; C:\1.bin   I only have 1KB output with content inside said "unknown id". Also tried with pull but seems also doesn't work.  What should I do to get this 15.7 GB mmcblk0  ? At what stage should acknowledgements be inserted into the paper if review is not double-blind? When the review process is double-blind, I guess (although I have not read this anywhere) that acknowledgements should not be written in the submitted paper, as this might break anonimity. They should only be inserted into the camera-ready version, after the paper is accepted.  What is the custom when the review process is not double-blind? Should I write the acknowledgements in the submitted version, or wait to the camera-ready version?