What is the difference between sudo -i and sudo su?
What is the difference between the following commands:  su sudo -s sudo -i sudo bash   I know for su I need to know the root password, and for sudo I have to be in the sudoers file, but once executed what is difference?  I know there is a difference between su and sudo -s because my home directory is /root after I execute su, but my home directory is still /home/myname after sudo -s. But I suspect this is just a symptom of an underlying difference that I'm missing.
I can't get grub menu to show up during boot Mid 2012 MBP shuts down claiming no power with charge at 30% or 40% or more I have two mid 2012 MBPs. Sometime last year they both started randomly shutting down and showing the 'please plug me in to power' image when trying to start them up. That would be fine if the batter was at 1% or less but this happens when the battery is at anywhere from 30% to as high as 48% full. The power cycle info says 500 cycles or so. Both of them do this. They are both patched current, always. I asked Apple they suggested NVRAM PRAM and SMC reset, as expected, which had no effect. Any ideas? Attractive Boxed Equations Blank white desktop icons on new Windows 7 install Does the concept of infinity have any practical applications? I know what you're thinking: "of course it has, for example, it can be used to tell you how many times you can go around a circle". But that isn't really true, now is it? You'd be dead or the world would go under long before an infinite amount of loops had been reached.  Are there any practical applications for the concept of infinity? Is it a useful concept in maths at all?  I know that Donald E. Knuth has argued that for all practical purposes, a very, very large number has the same effect as infinity, in his book "Things a Computer Scientist Rarely Talks About" (can't remember the exact quote, nor find it online, unfortunately).  Examples are appreciated. Why can't the end code of an environment contain an argument? Environments are allowed to have arguments, but reference to those arguments can only appear in the opening code of the environment, and not the closing code.  What is the reason for this, and are there preferred ways around it?  e.g.  \newenvironment{foo}[1]% {some code #1} % allowed {some code #1} % not allowed Logistic regression vs. LDA as two-class classifiers I have read several introductory texts about LSTM online, but none of them give a rigorously mathematical explanation of what the model actually does. For instance, why does the forget gate forget any more than any of the other gates in the LSTM unit?  Which papers and/or books should I read if I want to get a deeper understanding of LSTM? Ubuntu 20.04 graphics driver problem I have upgraded from Ubuntu 19.10 to 20.04, and now I have a problem with my graphics rendering (strange squares on background and font problems). I use the i915 driver. Graphics card: Skylake GT2 HD Graphics 520. I tried to reinstall GNOME shell and Xorg server. Nothing helped. Also Chrome browser breaks on most of pages. Winter Bash 2014 Secret Hats Determine the exact date of creation of an Apple ID Is it possible to determine the exact date and time (if possible) of creation of an Apple ID?   Is there any official or unofficial way to establish this if you don't have the initial sign up information recorded? Is there a way to respec attributes? Execute a large SQL script (with GO commands) Choice of personal pronoun in single-author papers gnome-software on Ubuntu 16.04 doesn't work A problem about wave equation If $A$ and $B$ are square matrices such that $AB = I$, where $I$ is the identity matrix, show that $BA = I$.    I do not understand anything more than the following.   Elementary row operations. Linear dependence. Row reduced forms and their relations with the original matrix.   If the entries of the matrix are not from a mathematical structure which supports commutativity, what can we say about this problem?  P.S.: Please avoid using the transpose and/or inverse of a matrix. Adding coordinate system to layout in QGIS composer? Difference between "while" and "whilst" Possible Duplicate:          In terms of construction of sentences, can the two words while and whilst be used interchangeably? Disable two column mode for separate part I am writing a document using the report class in two column mode, but I need a \section to spread across both columns, but how can I set that?  Something like  \documentclass[10pt,danish,a4paper,twoside,twocolumn]{report} \input{preamble.tex} \begin{document}  % This section should spread over both columns \section{Name}  \lipsum[1-3] \end{document}