I have a file containing the following text:  we are going to write something 1 2 3   wc tells me I have 1 line 9 words and 38 characters.  I'm looking to count the 26 letters only (a-z, no numbers or white spaces etc).  Here's my current solution:  grep -o [[:alpha:]] filename | wc -l   I really want to know if there is a "better" way to do this at the command line.
I have a file with a number of lines in a file filename.  I want to count how many lines start with character 'a', with 'b' and so on in one go.  What command i should execute.?
Execute managebean method from javascript onload event I have a hard time finding a how-to.  I would like to set up a simple ESD mat and wrist wrap, but I am not sure about is the the 1 MOhm resistor should be, if at all.  Several options:   1 MOhm from ground outlet to the mat, wire from the common earthing on the mat to the wrist wrap. 1 MOhm from ground outlet to the mat, wire from another contact on the mat to the wrist wrap. 1 MOhm from ground outlet to the mat, 1 MOhm from the same mat contact to the wrist wrap. wire from ground outlet to the mat, 1 MOhm from the same mat contact to the wrist wrap. wire from ground outlet to the mat, wire from another mat contact to the wrist wrap.   I am not sure why the 1 MOhm wire is needed since the mat itself already has that kind of resistance (as long as the wrist wrap does not connect to ground directly, but through the mat).  Which solutions above are ok? Which is best? Should I do something else instead? How does delete[] know it's an array? How to do a generalized linear model with multiple dependent variables in R? Where and how can I view skype logs (Chat and Voice history)? Where and how can I view my skype logs (Chat and Voice history)? Does it get saved somewhere in PC by default? Can I choose a folder location myself to start saving voice and chat history? I have a problem with this limit, I don't know what method to use. I have no idea how to compute it. Is it possible to compute this limit with the McLaurin expansion? Can you explain the method and the steps used? Thanks. (I prefer to avoid to use L'Hospital's rule.)  $$\lim _{x\to 0}\frac{x\bigl(\sqrt{3e^x+e^{3x^2}}-2\bigr)}{4-(\cos x+1)^2}$$ Can Selenium interact with an existing browser session? I would like to use the sentence     He was 'over-eager' to implement his plan, leading to failure.   I am looking for a single word which expresses over-eagerness in a negative sense.  TIA An example of grey and white note that I mean is, like when you copy something, a small grey background and white lettered bubble appears for a few moments saying 'copied to clipboard'. My phone has some sort of malfunction where it dispays that prompt for several minutes at a time. Very annoying. How do I disable that? I am using a Samsung Galaxy S9. Compute $e^{e^z}$, where z is a complex number I am self-studying the MAT 67 linear algebra course and I got stuck at a problem in Chapter 2:     Compute the real and imaginary parts of $e^{e^z}$ for $z$ $\in$ $\Bbb C$.   I tried to expand it using Euler's formula but it seemed endless. Any help? Properties of invertible matrices Show that if $A$, $B$, and $A + B$ are invertible matrices with the same size, then   $A(A^{-1}+B^{-1})B(A+B)^{-1}=I$      What does the result in the first part tell you about the matrix $(A^{-1}+B^{-1})$?   I get the first part. Help me with the second part. I've found in Wikipedia the formula for calculating an individual row in Pascal's Triangle: $$v_c = v_{c-1}\left(\frac{r-c}{c}\right).$$ where $r = \mathrm{row}+1$, $c$ is the column starting from $0$ on left and $v_0 = 1$.  Now, I've tried to do by hand and it works,  but I don't understand how to find this magic formula when I don't have access to Wikipedia...:) How can I gzip standard in to a file and also print standard in to standard out? I have built a forecasting model for a company. Since it is dedicated to practical usage, I prefer to use the relative error parameter (like MAPE, SMAPE, &amp; MASE) as a measurement for my model performance and display it on the dashboard (the percentage error is easier to understand by user). I found an interesting reference about the criteria of a good forecast result based on MAPE from Lewis (1982):  ...but in my case, I can't use MAPE for some dataset because there is some zero actual demand so it can't be used as denominator in MAPE. So, I use SMAPE &amp; MASE instead, but I can't find any good references about good forecast result criteria based on SMAPE &amp; MASE, nothing like above. So, I'd really appreciate any help/suggestion about it :), Thank You! Reference: Lewis, C. D., 1982. Industrial and Business Forecasting Methods. London: Butterworths. .NET OpenSource projects and strong named assemblies? Which Ubuntu repositories are totally safe and free from malware? Let $S$ and $W$ be subsets of a vector space $V$. Show that if $S$ is a subset of $W$, then $\mathrm{span}(S)$ is a subspace of $\mathrm{span}(W)$ Let $S$ and $W$ be subsets of a vector space $V$. Show that if $S$ is a subset of $W$, then $\mathrm{span}(S)$ is a subspace of $\mathrm{span}(W)$.  Ok I'm finally understanding what each of these things mean.. but I'm running out of ideas on how to actually show it without using arbitrary vector space examples like Rn. Since sets and subspaces are kind of new its hard to figure out how to write correct proofs with them.   I can see how if $V = \mathbb{R}^3$ and $S = \{(1,1,1)\}$ and $W = \{(1,1,1), (1,1,2)\}$ then $\mathrm{span}(S) = R1(line), span(W) = R2(plane)$ and that R1 is a subspace of R2... im just having trouble showing this officially when all vector spaces and sets are completely in general....  I could get as far as writing out $S=(u_1,u_2,\dots,u_n)$, $u_i \in V$ and same with $W$, but I can't really figure out what else to do in this sort of proof. What is the effect of having correlated predictors in a multiple regression model? I learned in my linear models class that if two predictors are correlated and both are included in a model, one will be insignificant. For example, assume the size of a house and the number of bedrooms are correlated. When predicting the cost of a house using these two predictors, one of them can be dropped because they are both providing a lot of the same information. Intuitively, this makes sense, but I have a some more technical questions:   How does this effect manifest itself in p-values of the regression coefficients when including only one or including both predictors in the model? How does the variance of the regression coefficients get affected by including both predictors in the model or just having one? How do I know which predictor the model will choose to be less significant? How does including only one or including both predictors change the value/variance of my forecasted cost? $VAR vs ${VAR} and to quote or not to quote It is a question of Nautilus file manager of Ubuntu 18.04. Is there a simple way to create a Folder when file list is full of items?