I would like to know if it's possible to load only 1 web page when Linux logs on with an automatic user. This server will be used only to display information, no interaction is required and even if the end user wants to interact with the X window / Window Manager (opening another window, running other apps, switching users, switching to Virtual consoles), he'll not be able to do (the Window manager will not let him).  I don't have in mind a specific Linux distribution or window manager, but more looking to see first if it's possible or not.  I looked on the Internet (Window managers, X window, embedded Linux), but I didn't find anything useful for my case  Don't hesitate to contact me if you need more clarification regarding my need.
Is it possible to add a user and restrict him to run special programs? For example after this user logs in, he can only open Firefox to use Internet and no other programs can be run by this user. For example in a terminal, commands will not be accessible when you delete some environment variables like $HOME. But is it possible to avoid running programs in a graphical shell, like Gnome? If yes, how?
Why can't I change directories using "cd" in a script? I just did my first install of any Linux OS, and I accidentally selected "Desktop GUI" in the install, but I want to build everything myself. Is there any way by which I can remove the GUI environment without re-installing OS? Enumerated description list How can a list be created, whose items are both    enumerated (a,b,c,d,...)  and allow for setting a description via \item[texthere] ?   Im am using MikTex on Windows. How can I read my hard drive’s SMART status in Windows 7? How can I read the  S.M.A.R.T. state of my HDDs while using Windows 7, either automatically or manually? Why is there a peeking duck in my profile pic? In , you may see something odd: a peeking duck.    I've just recently uploaded this new profile picture of mine. I checked it after the upload and everything's fine. After a few hours, I opened my profile and there it is, the duck has somehow become afraid of the people viewing it.  Is this a bug, a feature, or is it just the duck?  I am about to re-upload my profile pic, but I've decided to drop first this topic to meta.  And if you're curious,  is the original picture.    ADDITIONAL: I've used the non-gravatar way to upload the picture.  ADDITIONAL 2: The problem only shows in the profile view. No problem in chat, less info profile view, and in the questions and answers.  UPDATE: Re-uploaded picture. Status normal (for now, at least). I can't execute newest Blender 2.80, it says that I need a graphics card that supports OpenGL 3.3 or higher ERROR: A graphics card and driver with support for OpenGL 3.3 or higher is required  Processor: AMD A6-3670 APU with Radeon(tm) HD Graphics, 2695MHz BIOS Version: HPQOEM - 1072009 Dedicated GPU:   This is a very old PC, but when I search online it seems that theoretically Blender 2.8 should run since my openGL is 4.4 Cross-referencing problem if counter of theorem-like environments is shared The problem is when i share numbering the \cref can't show name, even by \crefname and \autoref show all name Equation.  Here is an MWE:  %&amp;latex \documentclass{amsart}  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % If you want to insert other packages. Insert them here \usepackage{amsthm} \usepackage{hyperref} \usepackage[nameinlink]{cleveref} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%  \begin{document}  \numberwithin{equation}{section}  \newtheorem{The}[equation]{Theorem} \crefname{The}{Theorem}{Theorems}  \newtheorem{Dfn}[equation]{Definition} \newtheorem{Lem}[equation]{Lemma} \newtheorem{Prs}[equation]{Proposition} \newtheorem{Crl}[equation]{Corollary} \newtheorem{Rmk}[equation]{Remark}  \begin{The}\label{T1}    Assume ... \end{The}  ... \begin{Dfn}\label{D1}    Assume ... \end{Dfn}  ... \begin{Lem}\label{L1}    Assume ... \end{Lem}  ... \begin{Prs}\label{P1}    Assume ... \end{Prs}  ... \begin{Crl}\label{C1}    Assume ... \end{Crl}  ... \begin{Rmk}\label{R1}    Assume ... \end{Rmk}  \begin{equation}\label{E1}    Assume ... \bigskip \end{equation}  \noindent \cref{T1} \\ \cref{D1} \\ \cref{L1} \\ \cref{P1} \\ \cref{C1} \\ \cref{R1} \\ \cref{E1} \\  \noindent \autoref{T1} \\ \autoref{D1} \\ \autoref{L1} \\ \autoref{P1} \\ \autoref{C1} \\ \autoref{R1} \\ \autoref{E1} \\  \end{document}     How can I solve it? Can the program counter on Intel CPUs can be read directly (that is without 'tricks') in kernel mode or some other mode? What's the term in music, where the singer uses words without meaning? I've been searching for the word, which is used for describing parts of lyrics, where the singer sings for example the whole refrain only using words of syllables without any meaning. Maybe you could help? (here's one song with that type of refrain: ) No cycle containing edges $e$ and $g$ implies there is a vertex $u$ so that every path sharing one end with $e$ and another with $g$ contains $u$ There is a proof in my textbook for the following claim, which doesn't make a whole lot of sense to me.  My annotations are in bold.  Could someone perhaps elaborate on what's going on?  Claim.  If there does not exist a cycle containing edges $e$ and $g$ then there exists a vertex $u \in V (G)$ such that every path in $G$ sharing one end with e and another with $g$ contains $u$.  Proof: The claim trivially holds if $e$ or $g$ is a loop OK, so we assume that neither is. Let $P$ with vertex set $v_1, v_2, . . . , v_k,$ in order, be a path with $e$ joining $v_1$ to $v_2$ and $g$ joining $v_{k−1}$ and $v_k$. Let $f_i \in E(P_i)$ be the edge with ends $v_i$ and $v_{i+1}$. Let $j$ be chosen minimum so that no cycle in $G$ contains $e$ and $f_j$ We can do this because we know that at least the edge $g$ will not create a cycle by assumption, right?. We will show that $u = v_j$ satisfies the claim.  Suppose not. Let $C$ be a cycle containing $e$ and $f_{j−1}$ What if $f_j = e$?  then what cycle? a single vertex? and let $P′$ be a path from an end of $e$ to an end of $f$ Not sure what the book meant by $f$ here, any guesses? avoiding $u$. Choose a subpath $Q$ of $P′$ with one end in $V (C)$ and another in ${v_{j+1}, v_{j+2}, . . . , v_k}$ as short as possible. Then $C \cup Q \cup P$ contains a cycle containing both $e$ and $f_j$, a contradiction. (The last statement requires some case checking.) This ending seems a bit abrupt and non-obvious to me  Thanks for the help Variable declaration placement in C I long thought that in C, all variables had to be declared at the beginning of the function. I know that in C99, the rules are the same as in C++, but what are the variable declaration placement rules for C89/ANSI C?  The following code compiles successfully with gcc -std=c89 and gcc -ansi:  #include &lt;stdio.h&gt; int main() {     int i;     for (i = 0; i &lt; 10; i++) {         char c = (i % 95) + 32;         printf("%i: %c\n", i, c);         char *s;         s = "some string";         puts(s);     }     return 0; }   Shouldn't the declarations of c and s cause an error in C89/ANSI mode? Let $R$ be a simple ring and $T$ be a non-zero ring. Let $f\colon R \rightarrow T$ be a ring homomorphism. Show $f$ is injective.  Proof: $\ker f \lhd R$, so $\ker f=R$ or $\ker f=\{0\}$. If $\ker f=R$ then $R/R \cong \{0\}$, but $T \neq \{0\}$, which is a contradiction. I can't see why does the last part means contradiction.   Thanks for any assistance! Possible Duplicate:          The square root of a number squared is equal to the absolute value of that number. Why is $\sqrt{x^2} = |x|$? Why not just $x$? Please give me a reason and also help me prove it. Easier/better way to compute and store a value that's accessed as a property? Unexpected results when mounting two drives on a single mount point I was running out of /tmp space on one of my servers today so I attached a new 100GB disk to the system and did the following without unmounting /usr/tmpDSK from /tmp:  mkfs.ext4 /dev/xvde mount /dev/xvde /tmp   and now df -h outputs as:  Filesystem      Size  Used Avail Use% Mounted on /usr/tmpDSK      98G  4.5G   89G   5% /tmp /dev/xvde        98G  4.5G   89G   5% /tmp    The size of /usr/tmpDSK shows :  [root@server2 usr]# ll -h /usr/tmpDSK -rw------- 1 root root 2.3G Jan 27 17:32 /usr/tmpDSK    Different forums suggested using mhddfs to mount multiple drives on a single mount point, but I just did it directly and it seems to have worked -- or am I missing something?  I am hoping to better understand what actually happened. Fortunately, I can still login with this email address that I have lost access to.  I have been searching around here for a way to update it to the current one I use.  I have found many answers.  But they all give instructions to click on something not displayed or in one case, a page that prompts me to login via another email I no longer have the password for. I need current up to date instructions on how to change my email address or add another email-based login for this same user name that I am posting this with. I have been using LaTeX for a long time now, and I find myself often going to this website to solve my problems. This often includes copy pasting codes which include \newcommand, \newenvironment and \def. I think it is time I start to learn how to use them so I can solve my problems myself! It is always better if you actually know what is going on inside your code.  I am wondering if there is any turtorial or book out there that handles how to use those commands. Or is the best way to learn to just mess with a random file?   Thanks in advance!  (Also this is my first time I post here after using this website for so long, I really appreciate everyone who posts and tries to help other people here!) Is there a notification mechanism for when a dependency property has changed? 3D graphics render as though no illumination alias or bash function does not work When I create  alias wd='ps -ef | grep java | awk {'print $2 " " $9'} | egrep "(A|B|C|D)"'   or  function wd () {     ps -ef | grep java | awk '{print $2}' ... }   in my .bashrc file, I get errors.  Interestingly, if I source my .bashrc file with the function, it 'compiles', but when executing, gives me:   context is      &gt;&gt;&gt; \ &lt;&lt;&lt; {\print     missing }   Can someone help me with this, and also answer when its better to put something in a function versus in an alias?