I have a simple setup like this:  SERVER ---- INTERNET ---- CLIENT  On SERVER I already have OpenVPN set up with a sertificate for CLIENT. On CLIENT I already have OpenVPN set up to contact the server using its key and this is working fine.  Now I would like to set up another OpenVPN connection between SERVER and CLIENT with different settings (lets say the first is TCP and the other is UDP for example).  In this scenario, can I reuse the certificate/key from the first connection in the configuration of the second?  Is this a good practice? Why/Why not? Any caveats to know about?
We are experimenting with running an OpenVPN server for our business. One question I can't seem to find the answer to is this:  When we generate keys for one of our users for them to use at home, can their use the same keys on their home laptop as well as their home desktop? Or do we need to generate separate keys for each user's client machine?
Grabbing the first [x] characters for a string from a pipe Sum of two uniform random variables MCMC in a frequentist setting I have been trying to get a sense of the different problems in frequentist settings where MCMC is used. I am familiar that MCMC (or Monte Carlo) is used in fitting GLMMs and in maybe Monte Carlo EM algorithms. Are there more frequentist problems where MCMC is used? I use Gedit a lot and thus tend to have a lot of tabs open at any one time. In Gedit 2.* I could switch between tabs using my mouse wheel but since Oneiric I can't. I assume this is because of various GTK "upgrades".  Does anybody know of a plugin (or workable fix -- that doesn't require me to recompile everything and its brother) that will see me back to mousewheeling my day away? jQuery ajax load() java script not executing? Proper use of the IDisposable interface I know from reading  that the "primary" use of the IDisposable interface is to clean up unmanaged resources.  To me, "unmanaged" means things like database connections, sockets, window handles, etc.  But, I've seen code where the Dispose() method is implemented to free managed resources, which seems redundant to me, since the garbage collector should take care of that for you.  For example:  public class MyCollection : IDisposable {     private List&lt;String&gt; _theList = new List&lt;String&gt;();     private Dictionary&lt;String, Point&gt; _theDict = new Dictionary&lt;String, Point&gt;();      // Die, clear it up! (free unmanaged resources)     public void Dispose()     {         _theList.clear();         _theDict.clear();         _theList = null;         _theDict = null;     }   My question is, does this make the garbage collector free memory used by MyCollection any faster than it normally would?  edit:  So far people have posted some good examples of using IDisposable to clean up unmanaged resources such as database connections and bitmaps.  But suppose that _theList in the above code contained a million strings, and you wanted to free that memory now, rather than waiting for the garbage collector.  Would the above code accomplish that? Alignment issue in users page while searching user Fixed points under action of conjugate group elements Lecture notes:  If $g$ and $h$ are conjugate then $fix(g)=fix(h)$. To see this, say $g=k^{-1}hk$  If $g.s=s \iff k^{-1}hk.s=s \iff h.(k.s)=(k.s)$  Me: I understand the last line- I just fail to see how it implies $fix(g)=fix(h)$  EDIT: As Ben S says I think there was a typo in the notes and they forgot modulus signs so- New Aim: show $|fix(g)|=|fix(h)|$ Do the parent directory's permissions matter when accessing a subdirectory? Wanted: question mark instead of bibtex key for missing citations (biblatex) Instead of having the citation key showing up in the document for missing references, I want to only have [?], as it is the case when using the default bibtex without biblatex. This behavior is driving me crazy, as it messes up all the formatting (especially in tables). I want to focus on writing and only later on deal with the erroneous citations.  This question is related to    and its MWE can be used. However, as pointed out beforehand, I want the question mark in the text instead of the citation key to not mess up the formatting (for missing citations). I'm experiencing a bug where when the machine comes back from standby a monitor connected via displayport (MST) does not come back on, however the windows are still in the area it cover if it did come on.  The only way to recover from this short of a restart is to disable and reenable the display now I can do that via the command line just fine but when the display is disabled all the windows get rearranged onto the remaining screen.  Is there a way to persist the window positions and restore them so my script could do this sequence:-   enumerate windows, store positions display off (messing up positions) display on (making the display work again, yay!)  restore position of the windows   I can do step 2 and 3 just fine but I'm lost for step 1 and 4  I know I can force a position per app but that's not what I want as I could be doing different things and have the same apps in different positions, I also have multiple terminals open, I need the current positions storing somehow and restoring.  Any help would be appreciated! This is a  about IPv6 Subnetting.      Related:               I know a lot about , and as I prepare to (deploy|work on) an IPv6 network I need to know how much of this knowledge is transferable and what I still need to learn. IPv6 seems at first glance to be much more complex than IPv4. So I would like to know:   IPv6 is 128 bits, so why is /64 the smallest recommended subnet for hosts? Related to this:   Why is it recommended to use /127 for point to point links between routers, and why was it recommended against in the past? Should I change existing router links to use /127? Why would virtual machines be provisioned with less than a /64 worth of addresses? Are there other situations in which I would use a subnet smaller than /64?  Can I map directly from IPv4 subnets to IPv6 subnets? For instance, does an IPv4 /24 correspond directly to an IPv6 /56 or /120? My interfaces have several IPv6 addresses. Must the subnet be the same for all of them? Why do I sometimes see a % rather than a / in an IPv6 address and what does it mean? Am I wasting too many subnets? Aren't we just going to run out again? In what other major ways is IPv6 subnetting different from IPv4 subnetting? Make OS X Terminal commands I type BOLD I'd like to make commands I've typed (input) into terminal stand out from all the output.   For example:  imac:~ buster$ chmod -R g-w myfolder  imac:~ buster$ cd myfolder imac:myfolder buster$ ls -l total 0 drwxr-xr-x   9 root  admin   306 Apr 20  2010 bin drwxr-xr-x   7 root  admin   238 Apr 20  2010 include drwxr-xr-x  73 root  admin  2482 May 18 17:16 lib drwxr-xr-x   6 root  admin   204 Apr 20  2010 man imac:myfolder buster$ echo Go Giants! Go Giants!  bold jumps to mind but I'd accept a color or even highlighting the whole line...   I'm sure there's a way to do this but it's not obvious to me...  thanks! This might be a stupid question, but I just don't get it. In Hamiltonian mechanics when examining conditions for a $(\boldsymbol{q},\boldsymbol{p})\rightarrow(\boldsymbol{Q},\boldsymbol{P})$ transformation to be canonical one starts with $$ \dot{q}_ip^i-H(\boldsymbol{q},\boldsymbol{p},t)= \dot{Q}_iP^i-\bar{H}(\boldsymbol{Q},\boldsymbol{P},t)+\frac{d}{dt}W(\boldsymbol{q},\boldsymbol{Q},t)$$ where $\bar{H}$ is the transformed Hamiltonian, and $W$ is the generating function (now a function of $\boldsymbol{q}$ and $\boldsymbol{Q}$). This term shouldn't break Hamilton's principle, since $$ \delta\int_{t_1}^{t_2} dt\frac{d}{dt}W(\boldsymbol{q},\boldsymbol{Q},t)=\delta W(\boldsymbol{q},\boldsymbol{Q},t)|_{t_2}-\delta W(\boldsymbol{q},\boldsymbol{Q},t)|_{t_1}=0-0=0 .$$ But I don't see why the variation of $W$ should disappear at the endpoints (say at $t_1$). Expanding leads to: $$ \delta W(\boldsymbol{q},\boldsymbol{Q},t)|_{t_1}=\left(\frac{\partial W}{\partial q_i}\right)_{t_1}\underbrace{\delta q_i(t_1)}_{=0}+ \left(\frac{\partial W}{\partial Q_i}\right)_{t_1}\delta Q_i(t_1)=\left(\frac{\partial W}{\partial Q_i}\right)_{t_1}\delta Q_i(t_1).$$ $\boldsymbol{Q}$ is itself a function of $\boldsymbol{q}$ and $\boldsymbol{p}$, so $$ \delta Q_i(t_1)=\left(\frac{\partial Q_i}{\partial q_k}\right)_{t_1}\underbrace{\delta q_k(t_1)}_{=0}+\left(\frac{\partial Q_i}{\partial p_k}\right)_{t_1}\delta p_k(t_1)=\left(\frac{\partial Q_i}{\partial p_k}\right)_{t_1}\delta p_k(t_1). $$ It seems as if we also needed the variation of $\boldsymbol{p}$ to vanish at the endpoints, and I don't get this because (at least in cartesian coordinates) $\boldsymbol{p}=m\dot{\boldsymbol{q}}$ and the velocity can be different along the original and the varied orbitals even at the endpoints (they can point in totally different directions), so in general $\delta \dot{\boldsymbol{q}}(t_1)\neq 0$. What am I doing wrong? Can someone help me with this, please? How to avoid the 'not properly formatted as code' alert How do you backup all your emails, by copying the 'Outlook' folder? (Outlook 2013) [...] All versions of Outlook use pst files, but the disk location has changed over the years. Right-click your email account on the left in Outlook and select Data File Properties. Click Advanced to see the filename. Only the pst file is essential, but copy the whole folder to back up Outlook’s settings and preferences too. Just copy it back to restore it, or click File, Open, Open Outlook Data File. Outlook can work with any pst file stored anywhere.  Backing up your Outlook data file(s) is as easy as copying your .OST or .PST files over to another hard drive, cloud server, thumb drive, or some other storage medium. You remember how to locate your data files? Open the Mail control panel and click the “Data Files” button. Click “Open File Location…” and you can then back up your data files. [I don't display  here)  After following the instructions above, I arrive at:  C:\Users\[my username]\AppData\Local\Microsoft\Outlook  However, all Outlook Data Files here are .ost, and NOT .pst. In  File &gt; Open &amp; Export &gt; Open Outlook Data File, 'Open Outlook Data File' only works for .pst. What is wrong here? Where's the folder with all the .pst files? How can I backup all my Outlook email accounts simultaneously? $\chi(G)+\chi(G')\leq n+1$ How to prove, that the sum of chromatic numbers of graph and it's complement is smaller then the number of vertices incremented by one?  $\chi(G)+\chi(G')\leq n+1$  The notes from my classes say to color the first graph using sequential algorithm with vertices ordered by their degrees (the ones with lowest appear first). We would get $k_1$ colors, then we color the graph $G'$ in the backwards order and get $k_2$ colors, and the sum $k_1+k_2$ in my notes is magically smaller than $n+1$, but I just don't see why... Find the asymptotic tight bound in  $$ T(n) = 4T\left(\frac{n}{2}\right) + n^{2}\log n. $$  where $ \log n= \log _{2}n $ and $T(1) = 1$.  I should solve this using all three common methods: iteration, master theorem and substitution.  It is highly likely that this kind of recurrence equation will be in my test in two days. Thank you very much in advance! Why were the villagers and the axe-wielding hitman brothers crawling towards a shrine? At the start of Season 3 Breaking Bad, we see a bunch of villagers and Tuco's cousins crawling on their bellies towards some shrine where they put a drawing of Walter White as some kind of "offering".  Why were the villagers and the cousins crawling towards this shrine? Surface area inside cylinder Find the surface area of the part $\sigma$: $x^2+y^2+z^2=4$ that lies inside the cylinder $x^2+y^2=2y$  So, the surface is a sphere of $R=2$. It looks there should be double integral to calculate the surface, but how, which way?