This command to rename all files fails: "find: 'rename': No such file or directory" Trying to replace all file names in a directory with ai to newai.  Execute: find . -exec rename 's/ai/newai/' {} ";" Error: find: ‘rename’: No such file or directory   What could be the problem here, and how can I fix it?
Rename command not found when running a script I'm trying to to execute a script, which uses the command rename.   When I execute it, I get a message rename: command not found. Any ideas?   if [[ -z '$3' ]]; then     shopt -s dotglob     rename "$EXPRESSION" ./* else     rename "$EXPRESSION" "$3" fi
Exactly what the name entails. The function $2^n-1$ I see largely tends to generate primes when $n$ is prime. However, a week ago I heard that this was horribly false. Please show me a disproof. How to install Microsoft fonts on Ubuntu 16.10? Consider the subset $B=\{(x,y):x^2+y^2\leq 1\}\ \subseteq \mathbb{R}^2$. Show that $\vert B \vert = \vert \mathbb{R}^2 \vert$.  It is easy to see tht $f:B\rightarrow\mathbb{R}^2$ defined as $f(x,y)=(x,y)$ is injective.   However, in the book I'm working out of (Book of Proof by Richard Hammack), the other injection noted is  $g:\mathbb{R}^2\rightarrow B$ defined as  $$g(x,y)=\left(\frac{x^2+y^2}{x^2+y^2+1}x,\frac{x^2+y^2}{x^2+y^2+1}y\right).$$  In the book I'm asked to verify this is indeed an injective function.  My approach was to assume $g(x,y)=g(m,n)$ and through basic algebra I was able to deduce  $x(m^2+n^2+1)(x^2+y^2)=m(x^2+y^2+1)(m^2+n^2)$  and  $y(m^2+n^2+1)(x^2+y^2)=n(x^2+y^2+1)(m^2+n^2)$  but how does this show $(x,y)=(m,n)$? Or is this the wrong approach? How to prove that derivatives have the Intermediate Value Property Why didn't Dumbledore prevent the prosecution of Sirius Black? Dumbledore performed the Fidelius charm on the Potters, so he knew who the Secret-Keeper was1. That implies he knew not Sirius but Wormtail betrayed the Potters. Why didn't he prevent Sirius's conviction and suspect the explosion killing twelve Muggles was caused by Wormtail (and that Sirius cornered Wormtail instead of the other way around)?   1: Though in  it is said Dumbledore didn't know. I find it hard to believe the person casting the Fidelius charm doesn't know who the Secret-Keeper is. Generating data with a given sample covariance matrix Printer "Filter failed" Upgraded to 18.04 from 16.04. I have a workplace printer connected through appsocket which stopped working.  Printer status is Idle-Filter failed.  Printing queue instantly goes to "stopped".  Right clicking on the printer shows "option finishings has value 3 and cannot be changed". I can't find any info on this error except one pdf to ignore the error.  The printer model Ricoh MP 2555 worked previously with the Ricoh MP C2800 driver. Now it works with neither 2800 or 2555.  The IP address of the printer pings fine. When I try and detect the printer on the network using IP address and I ask it to use the Ricoh MP 2555 driver, it asks for an additional driver which opens Ubuntu software (which never helps) and fails.  I tried changing drivers from "" by providing the ppd file. It still doesn't help. var/log/cups/error.log doesn't tell much, or I don't get it.  Hope someone knows about this error or some kind of a generic solution. EDIT Like some comments below are remarking the table environment doesn't allow tables over more than one page. However the solution works fine  I need to make a table over more than one page. The standard approach seems to be to use the ltablex environment. However, it doesn't work; also I assume that the table environment may also be required for the thesis template I work on (e.g. suppose for the capture).   \documentclass[11pt]{article} \usepackage{booktabs} \usepackage{tabularx} \usepackage{ltablex}  \begin{document}  \begin{table} \caption{Example of an table} \label{tab:daypack}      \begin{tabularx}{\linewidth}{@{}cX@{}}   \toprule \textbf{Column 1} &amp; \textbf{Column 2} \\[6pt] \midrule \endhead $R$ &amp; 1This is an example sentence \\[6pt] $R$ &amp; 2As well as the line before \\[6pt] $A$ &amp; 3Also this is an example \\[6pt] $R$ &amp; 4This is an example sentence \\[6pt] $R$ &amp; 5As well as the line before \\[6pt] $A$ &amp; 6Also this is an example \\[6pt] $R$ &amp; 7This is an example sentence \\[6pt] $R$ &amp; 8As well as the line before \\[6pt] $A$ &amp; 9Also this is an example \\[6pt] $R$ &amp; 10This is an example sentence \\[6pt] $R$ &amp; 11As well as the line before \\[6pt] $A$ &amp; 12Also this is an example \\[6pt] $R$ &amp; 13This is an example sentence \\[6pt] $R$ &amp; 14As well as the line before \\[6pt] $A$ &amp; 15Also this is an example \\[6pt] $R$ &amp; 16This is an example sentence \\[6pt] $R$ &amp; 17As well as the line before \\[6pt] $A$ &amp; 18Also this is an example \\[6pt] $R$ &amp; 19This is an example sentence \\[6pt] $R$ &amp; 20As well as the line before \\[6pt] $A$ &amp; 21Also this is an example \\[6pt] $R$ &amp; 22This is an example sentence \\[6pt] $R$ &amp; 23As well as the line before \\[6pt] $A$ &amp; 24Also this is an example \\[6pt] $R$ &amp; 25This is an example sentence \\[6pt] $R$ &amp; 26As well as the line before \\[6pt] $A$ &amp; 27Also this is an example \\[6pt] $R$ &amp; 28This is an example sentence \\[6pt] $R$ &amp; 29As well as the line before \\[6pt] $A$ &amp; 30Also this is an example \\[6pt] $R$ &amp; 31This is an example sentence \\[6pt] $R$ &amp; 32As well as the line before \\[6pt] $A$ &amp; 33Also this is an example \\[6pt] $R$ &amp; 34This is an example sentence \\[6pt] $R$ &amp; 35As well as the line before \\[6pt] $A$ &amp; 36Also this is an example \\[6pt] $R$ &amp; 37This is an example sentence \\[6pt] \bottomrule \end{tabularx}    \end{table}      \end{document} Override back button to act like home button What WordPress API function lists active/inactive plugins? What is the difference between class and instance attributes? Is there any meaningful distinction between:  class A(object):     foo = 5   # some default value   vs.  class B(object):     def __init__(self, foo=5):         self.foo = foo   If you're creating a lot of instances, is there any difference in performance or space requirements for the two styles? When you read the code, do you consider the meaning of the two styles to be significantly different? Suppress Chrome 'Failed to load resource' messages in console Order of redirections I don't quite understand how the computer reads this command.  cat file1 file2 1&gt; file.txt 2&gt;&amp;1  If I understand, 2&gt;&amp;1 simply redirect Standard Error to Standard Output.  By that logic, the command reads to me as follows:    concatenate files file1 and file2.  send stdout from this operation to file.txt. send stderr to stdout. end?   I'm not sure what the computer's doing. By my logic, the command should be   cat file1 file2 2&gt;&amp;1 &gt; file.txt   but this is not correct. Calculate mean of ordinal variable I've read in a number of places that calculating the mean of an ordinal variable is inappropriate. I'm trying to get an intuition for why it might be inappropriate. I think it is because, in general, an ordinal variable is not normally distributed and so calculating the mean will give an inaccurate representation. Could somebody give more detailed reasoning for why calculating the mean of an ordinal variable might be inappropriate? How do I insert the total continuation count in the allowframbreaks frame title? I would like to change the numbering of allowframbreaks frame, for instance, from I II III to (1/3) (2/3) (3/3)， but fail to find out a command to get the total continuation count. Here is the MWE.  \documentclass[compress]{beamer} \usetheme{Warsaw}   %allowframebreaks numbering in the title \setbeamertemplate{frametitle continuation}{(\insertcontinuationcount/)} %\setbeamertemplate{frametitle continuation}{(\insertcontinuationcount/\inserttotalcontinuationcount)}  \title{title} \author{author}  %%%%% \begin{document}  \begin{frame}[allowframebreaks]{allowframebreaks title} frame 1 \framebreak  frame 2 \framebreak  frame 3 \framebreak \end{frame}  \end{document} I'm working on a WordPress site for my band and I'd like to mark every 3rd post on our blog page to have a special class applied to it, anybody have any pointers on how to achieve this? Any help is very very appreciated, thanks! rock n roll. When is R squared negative? My understanding is that $R^2$ cannot be negative as it is the square of R. However I ran a simple linear regression in SPSS with a single independent variable and a dependent variable. My SPSS output give me a negative value for $R^2$. If I was to calculate this by hand from R then $R^2$ would be  positive. What has SPSS done to calculate this as negative?   R=-.395 R squared =-.156 B (un-standardized)=-1261.611   Code I've used:  DATASET ACTIVATE DataSet1.  REGRESSION /MISSING LISTWISE /STATISTICS COEFF OUTS R ANOVA             /CRITERIA=PIN(.05) POUT(.10) /NOORIGIN             /DEPENDENT valueP /METHOD=ENTER ageP   I get a negative value. Can anyone explain what this means? Reference for general-topology Could normal users have an easier way to flag for migration? Ubuntu 20.04 Font and UI elements too big on login I'm running Ubuntu 20.04 on an ASUS X99-E-10G WS w/ an NVIDIA 1080Ti and an LG 4k 32&quot; monitor which persistently gets recognized as 27&quot;. When I log in, the text of certain UI elements is ~2x the normal size. After I go to settings/universal access and turn large text on and then off again, everything is the normal size I expect. Screenshot after logging in  After turning &quot;large text&quot; on  After turning &quot;large text&quot; off  How do I get the conditions I have after cycling the &quot;large text&quot; feature to be present immediately after booting? I have the 440 version of NVIDIA's drivers installed.