So I am delt with a very bad hand. As Windows user for nearly 10 years  I have an assignment which says  Create 7 users - 2 admin, 2 teachers and 3 students [DONE]  Create folder in Home - Admin Files,Teacher Files,Student Files [Done]  Now I have to be able to do this using terminal   Allow students read-only access to the files in the Student Files folder, and no access to the other folders. Allow teachers full access to all  files except the Admin Files folder, to which they have no access. Allow administrators full access to all files.   How do I change the file permission for the scenario above?  Thanks in Advance
Can you explain briefly the main concepts and command line tools used to manage file permissions?
How to reinstall kernels after accidental deletion with a separate boot partition and an encrypted LVM volume? My installation is a Ubuntu 12.04 64 bits (Classic "legacy" MBR - No  EFI/UEFI here) with two partition :   A separate boot partition An encrypted LUKS volume that contains the system Logical Volumes   I seems I accidentaly deleted all the current kernel files with:  sudo apt-get purge 'linux-image-3.8*'    I applied the updates with Ubuntu Software Update, rebooted and then: Ubuntu can't boot.  I tried to boot on a live DVD with a 14.04.1 Ubuntu and can still see my partitions (described later):  /dev/sda1 (boot) /dev/sda2 (Encrypted volume) /dev/sda5 (Logical Volume container)  What are the steps to recover/reinstall the kernel files and dependencies in order to cleanly reboot my installed system?  Thanks in advance I would like to cook frozen chicken breasts in a pressure cooker for shredding and making chicken mole.  I do not want to add anything except water, but I'm having a hard time finding specific guidelines on the time to cook frozen meats with no added ingredients or steps.   In my case, I have 3 pounds of frozen chicken breasts to cook.  What are the general rules to follow for frozen meats and, in my case, how long and at what heat should I cook this for? Does not the mass of those living on the Earth add on to the mass of the Earth or is it too negligible to be cared for? : Earth weighs about 13,170,000,000,000,000,000,000,000 pounds (or   5,974,000,000,000,000,000,000,000 kilograms). Since Earth is too big   to be placed on a scale, scientists use mathematics and the laws of   gravity to figure out Earth's weight.   So, this seems to be a constant. But I guess it doesn't consider the things that are on the earth, the trees, buildings, people, animals, water etc...  So, are all the above mentioned things' mass is too small or negligible to be left off? Short story collection about Transporter "Doors" I'm looking for a short story collection about different uses/inventions of transporter doors. I think it was just a single author collection, that I read in the early 2000s.  In each story these Transporter Doors exist, I seem to remember them being described as blank grey sheets. You step through them and come out somewhere else. The forward to the book talked about early Rocket stories where the launch of a spaceship would be the end of the tale.  Plots of the individual stories:  Two men one of whom's home is inside an asteroid are discussing the use of Base12 in their society and if it is because they have 12 fingers, one says that "people" used to use base10. The implication is that a different species arrived through the doors and replaced humans.  A man puts the code for his home into a door and is instead transported to prison where he's accused of murdering his wife, which he strongly denies.   Two scientists and a pilot take a probe ship deep into Jupiter's atmosphere, the will return to base via a door that they need to construct while they are down there. The scientists dislike each other and don't work well together. When they finish the door, the hamsters seem woosy out the other side, but the scientists insist it is ready. The pilot says he will go first as he can't fix it if it's wrong. When he arrives on the far side he's mentally damaged and the scientists have to get along without him acting as a buffer while the try to save themselves. Biasing circuit - Voltage follower circuit Probability of success on third and fourth trials? I have a pretty basic probability question, but I'm just having difficulties remembering what distribution this is.  A coin is tossed until a head appears two times in a row. Given that we are using a fair coin, what is the probability that we toss the coin exactly 4 times such that the two consecutive heads are the 3rd and 4th trials?  I know that this would be fairly easy to solve by brute force and listing out the different probabilities, but I'm a little confused as to how to use a "shortcut" such as identifying this as a binomial distribution. I also don't know how to account for the probability that we are using 4 tosses.  Any help is appreciated. Thanks! How do you make Ubuntu accept files sent over bluetooth I have a problem when I send my files from phone to ubuntu 12.04 via bluetooth as the phone prompts with the message "the file not sent"! I can send any files from ubuntu 12.04 to my android phone. Ignore citations in captions in list of figures when numbering So I am using  package for code examples. But there is a problem. When I copy the code examples from the final PDF document, they are usually not the same - the indentation is gone, there are random spaces after parenthesis, etc. Does anyone know how to make sure that the code that I copy from the final document is the same as I wrote it in the LaTeX document?  Here is what I mean. Compile this document:  \documentclass[12pt,oneside]{memoir}  \usepackage{listings} \usepackage[T1]{fontenc} \usepackage{xcolor} \usepackage{textcomp}  \definecolor{codebg}{HTML}{EEEEEE} \definecolor{codeframe}{HTML}{CCCCCC}  \lstset{language=Awk} \lstset{backgroundcolor=\color{codebg}} \lstset{frame=single} \lstset{framesep=10pt} \lstset{rulecolor=\color{codeframe}} \lstset{upquote=true} \lstset{basicstyle=\ttfamily} \lstset{showstringspaces=false}  \begin{document}  This code example prints out all users on your system:  \begin{lstlisting}[language=c] #include &lt;stdio.h&gt; #include &lt;stdlib.h&gt; #include &lt;string.h&gt;  #define MAX_LINE_LEN 1024  int main() {     char line[MAX_LINE_LEN];     FILE *in = fopen("/etc/passwd", "r");     if (!in) exit(EXIT_FAILURE);      while (fgets(line, MAX_LINE_LEN, in) != NULL) {         char *sep = strchr(line, ':');         if (!sep) exit(EXIT_FAILURE);         *sep = '\0';         printf("%s\n", line);     }     fclose(in);     return EXIT_SUCCESS; } \end{lstlisting}  \end{document}   Now compile it, open it, select and copy the code example and paste it in a text editor. Here is the result I get:  # include &lt;stdio .h&gt; # include &lt;stdlib .h&gt; # include &lt;string .h&gt; # define MAX_LINE_LEN 1024 int main () { char line [ MAX_LINE_LEN ]; FILE *in = fopen ("/ etc / passwd ", "r"); if (! in) exit ( EXIT_FAILURE ); while ( fgets (line , MAX_LINE_LEN , in) != NULL ) { char * sep = strchr (line , ':'); if (! sep ) exit ( EXIT_FAILURE ); * sep = '\0 '; printf ("%s\n", line ); } fclose (in ); return EXIT_SUCCESS ; }   Jeez! What's this... The indentation is gone. There are spaces in included headers &lt;stdio .h&gt;, there are spaces after parenthesis [ MAX_LINE_LEN ].  Anyone knows how to fix this? I'd like the code examples in my book to be copy/paste-able into a text editor so people can try them out easily. SQL Server compatibility with New TLS Standards The major browsers are moving beyond SSL3.0 and TLS1.0 . The PCI Security Council has declared an end-of-life date for these protocols to be considered sufficiently strong encryption.   We need to move away from these protocols, to use newer and stronger ones. On Windows servers, you can very easily disable these old protocols, and instead offer only TLS1.1 or greater.  However, as noted , Microsoft SQL Server 2008 R2 and SQL Server 2012 (Standard, at least) both will not start if those lower protocols are disabled.  However, there are a growing number of versions of MS SQL Server.  There are SQL Server Standard, Business Intelligence, Enterprise, Express, Web, and Compact editions.  And of course there is SQL Server 2008, 2012, 2014, and (in pre-release) 2016.  Which of these editions support or will support the use of only TLS1.1 or greater protocols? How can I recover files from partitioned disk? biblatex: Cite commands with the same author prints authors name twice I'm using biblatex 1.4b, and Biber 0.9. However, I think the problem is with my settings, not with the versions of those programs.  I'm trying to cite a single author, and produce their name, followed by the dates of two papers, using the authoryear-ibid style, and natbib compatability. Here's my biblatex preamble:  \usepackage[style=authoryear-ibid,natbib=true,backend=biber]{biblatex}   What I want is for the following command: The works by \citet{Blau81, Blau88} ... to produce: The works by Blau (1981; 1988) ... however, what I'm getting is: The works by Blau (1981); Blau (1988)...  I know that biblatex knows they're the same author, since in the bibliography they fall under the same name (i.e. after the first instance of the name, there's just a dash instead of the name)  What am I doing wrong here? I've also tried it with the commands \cite and \cites, and neither produces what I want.   (crossposted with comp.text.tex) SEDE should pick up on changes to community metadata It appears that site meta data isn't updated in SEDE. As an example, Moderators.SE was  to  in December 2014. It is still listed in SEDE as Moderators.SE, as of July 2015.  To search for Community Building data, we need to search the "Moderators" community:    It is not listed as Community Building: On my system (Windows Vista Home Premium 64bit) Python files are associated with Python interpreter:  C:\Users\Piotr&gt;assoc .py .py=Python.File C:\Users\Piotr&gt;ftype Python.File Python.File=c:\python\2.7\python.exe "%1" %*   Nevertheless when I run any Python script from command line a window titled Open With pops up asking me to Choose the program you want to use to open this file. When is a function satisfying the Cauchy-Riemann equations holomorphic? It is, of course, one of the first results in basic complex analysis that a holomorphic function satisfies the Cauchy-Riemann equations when considered as a differentiable two-variable real function. I have always seen the converse as: if $f$ is continuously differentiable as a function from $U \subset \mathbb{R}^2$ to $\mathbb{R}^2$ and satisfies the Cauchy-Riemann equations, then it is holomorphic (see e.g. Stein and Shakarchi, or ). Why is the $C^1$ condition necessary? I don't see where this comes in to the proof below.   Assume that $u(x,y)$ and $v(x,y)$ are continuously differentiable and satisfy the Cauchy-Riemann equations. Let $h=h_1 + h_2i$. Then \begin{equation*} u(x+h_1, y+h_2) - u(x,y) = \frac{\partial u}{\partial x} h_1 + \frac{\partial u}{\partial y}h_2 + o(|h|) \end{equation*} and  \begin{equation*} v(x+h_1, y+h_2) - v(x,y) = \frac{\partial v}{\partial x} h_1 + \frac{\partial v}{\partial y} h_2 + o(|h|). \end{equation*} Multiplying the second equation by $i$ and adding the two together gives  \begin{align*} (u+iv)(z+h)-(u+iv)(z) &amp;= \frac{\partial u}{\partial x} h_1 + i \frac{\partial v}{\partial x} h_1 + \frac{\partial u}{\partial y} h_2 + i \frac{\partial v}{\partial y} h_2 + o(|h|)\\\  &amp;= \left( \frac{\partial u}{\partial x} + i \frac{\partial v}{\partial x} \right) (h_1+i h_2) + o(|h|). \end{align*}  Now dividing by $h$ gives us the desired result.   Does there exist a differentiable but not $C^1$ function $f: U \rightarrow \mathbb{R}^2$ which satisfies the Cauchy-Riemann equations and does NOT correspond to a complex-differentiable function? I watched this movie when I was a kid and never discovered it again.  It’s about a boy whose father left him after his divorce from the mother, the kid enters a world somehow where he has a big sword he needs to keep searching for precious stones to fill it with. it has certain holes that look like each stone shape! I also remember the kid going to eat with his mythical (dragon-like friend), and he gets stuck in the restaurant because the crazy restaurant lady won’t let him leave without finishing huge amounts of food!  The kid also gets bullied so I’m guessing the the swords journey is to teach the kid how to deal with all of this... How to modify the space between the numbers and text of sectioning titles in the table of contents? Why can't enum's constructor access static fields and methods? This is perfectly valid with a class, but is not allowed with an enum.  What I'm trying to do is store my enum instances in a static Map. Consider this example code which allows lookup by abbreivation:  public enum Day {     Sunday("Sun"), Monday("Mon"), Tuesday("Tue"), Wednesday("Wed"), Thursday("Thu"), Friday("Fri"), Saturday("Sat");      private final String abbreviation;      private static final Map&lt;String, Day&gt; ABBREV_MAP = new HashMap&lt;String, Day&gt;();      private Day(String abbreviation) {         this.abbreviation = abbreviation;         ABBREV_MAP.put(abbreviation, this);  // Not valid     }      public String getAbbreviation() {         return abbreviation;     }      public static Day getByAbbreviation(String abbreviation) {         return ABBREV_MAP.get(abbreviation);     } }   This will not work as enum doesn't allow static references in its constructor. It however works just find if implemented as a class:  public static final Day SUNDAY = new Day("Sunday", "Sun"); private Day(String name, String abbreviation) {     this.name = name;     this.abbreviation = abbreviation;     ABBREV_MAP.put(abbreviation, this);  // Valid } Just for curiosity, sometimes while installing software throught apt-get install software_name the terminal prompt me for a confirmation "type Yes or No", but not allways.  I dont mean the sudo password prompt, but the message "Will be downloaded and configrated XXX Kb, continue?" (or something similar)  Why? How to extract the last inserted row in SQL Server? When an insert statement is executed one or more rows is inserted into the table, is there any way to extract the last inserted row in SQL Server?