Regular expression for range of numbers
Regular Expression: Numeric range
Fake a webcam using a video loopback device? I want to use a looped video clip as my webcam source in a Google+ Hangout. I installed v4l2loopback and created a . But I haven't figured out how to write the video frames to the device. The given  is:  gst-launch videotestsrc ! v4l2sink device=/dev/video1   So after reading the manual page for gst-launch and trying to understand what was going on, I made my feeble attempt:  sudo gst-launch-0.10 filesrc location=/home/briankb/Videos/darthvaderdancing.mp4 ! v4l2sink device=/dev/video0   Which resulted in:  Setting pipeline to PAUSED ... libv4l2: error getting pixformat: Invalid argument Pipeline is PREROLLING ... Pipeline is PREROLLED ... Setting pipeline to PLAYING ...  (gst-launch-0.10:12622): GStreamer-CRITICAL **: gst_caps_get_structure: assertion `GST_IS_CAPS (caps)' failed New clock: GstSystemClock  (gst-launch-0.10:12622): GStreamer-CRITICAL **: gst_structure_get_name: assertion `structure != NULL' failed Caught SIGSEGV accessing address (nil) #0  0x00007fc1890f0b03 in poll () from /lib/x86_64-linux-gnu/libc.so.6 #1  0x00007fc18962bff6 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #2  0x00007fc18962c45a in g_main_loop_run () #3  0x00007fc189b5c4cb in gst_bus_poll () #4  0x0000000000404587 in ?? () #5  0x0000000000403c34 in ?? () #6  0x00007fc18902b76d in __libc_start_main () #7  0x00000000004043bd in ?? () #8  0x00007fff88253ed8 in ?? () #9  0x000000000000001c in ?? () #10 0x0000000000000006 in ?? () #11 0x00007fff882548c4 in ?? () #12 0x00007fff882548d4 in ?? () #13 0x00007fff882548dc in ?? () #14 0x00007fff88254904 in ?? () #15 0x00007fff88254906 in ?? () #16 0x00007fff8825490f in ?? () #17 0x0000000000000000 in ?? () Spinning.  Please run 'gdb gst-launch 12622' to continue debugging, Ctrl-C to quit, or Ctrl-\ to dump core.   The clip I'm trying to use an h264 video at 29.97 fps, 320x240, and in an mp4 container (it's from Youtube). Do creatures that enter the battlefield at the same time see each other enter? arccot limit: $\sum_{r=1}^{\infty}\cot ^{-1}(r^2+\frac{3}{4})$ Binding single key (such as 'F1') to multiple keys (such as 'Ctrl+C') in Gnome I know how to map a single key to a command using the gconf settings. I also know how to map a single key to another key (F1 -> ctrl) using Xmodmap. My question is how can I map a single key such as F1 to a multi-key operation such at ctrl+c. I am basically trying to set up a single key to simulate copy. I can think of two ways to possibly do this:   Map single key to multiple keys so that when the single key is pressed it is essentially pressing ctrl+c. Use gconf settings to execute the copy “command” upon the single key press. I am not sure if there is a “command” to copy text. How can I edit this trigger to only fire once? The trigger creates a related record when a checkbox is updated. The problem is it is creating a new related record everytime the record is edited. I want to edit the trigger to only create the related record once. (When the criteria is first met). The code is below  Trigger copyEquipmentonsite on Unit_Placements_Sales__c(after insert, after update) {      List&lt;Services__c&gt; sub=new List&lt;Services__c&gt;();      for(Unit_Placements_Sales__c u : Trigger.new) {           if(u.Service_Month_is_Next_Month__c == TRUE) {                 Services__c s = new Services__c();                 s.Equipment_Onsite__c=u.ID;                 s.Equipment_Type__c=u.Equipment__c;                 s.Machine_Specific_Notes__c=u.Machine_Specific_Notes__c;                    s.Product__c=u.The_Product__c;                   s.Dell_Tag_Number__c=u.Dell_Tag_Number__c;                 s.Serial_Number__c=u.Serial_Number__c;                  s.XD_Number__c=u.XD_Number__c;                 sub.add(s);           }           if(sub.size()&gt;0)           insert sub;      } } I want to make someone a present by subscribing for him to a mathematical journal. (It should appear every month or every two months). The contents should be comprehensible to an undergraduate in mathematics, and be about a broad selection of topics (for example not only analysis).   I expect the content to be something like proposing interesting problems and then giving solutions with some references for further study. Are there some famous journals you could suggest me? Re-install Ubuntu without losing data in home folder Recently I installed Ubuntu 12.10 x64 Server Edition on my PC. Unfortunately, I attempted to install a lightweight desktop but due to the fact that I have an old graphics card, the PC does not perform so well. I am thinking of re-installing an Ubuntu version but I do not want to lose the contents in my home folder. Is there any way to do that with a Live CD? SQL not engaging parallelism for extremely large query From :     "[...] the stress vector $T$ across a surface will always be a linear function of the surface's normal vector $n$, the unit-length vector that is perpendicular to it. [...] The linear relation between $T$ and $n$ follows from the fundamental laws of conservation of linear momentum and static equilibrium of forces, and is therefore mathematically exact, for any material and any stress situation. The components of the Cauchy stress tensor at every point in a material satisfy the equilibrium equations (Cauchy’s equations of motion for zero acceleration). Moreover, the principle of conservation of angular momentum implies that the stress tensor is symmetric."   What is the more detailed explanation for this, and/or where can I find it? If the earth would stop spinning, what would happen? How do I navigate to a samba location I've mounted in Nautilus on the command line? Please note: I am two weeks old in Linux. I have found a lot of answers to this question on the internet, tried many, but all failed one way or another. Therefore I dare to ask once again in the hope that someone here could explain it simply :)  Pre-conditions:  In my institute, we have a Samba server. In Windows, it is accessed by going to \\xyz.220.131.233\ and entering the login abc and the password def.   In Ubuntu, I was able to do exactly the same using Nautilus, pressing Ctrl+L and entering smb://xyz.220.131.233/. It then asks for the login and the password and connects. I can even drag a folder from here to the 'Places' and have a shortcut to the remote location.   So far so good. I've just installed Matlab and want to open this remote location. Trying to cd to smb://xyz.220.131.233/ returns      Cannot CD to smb://xyz.220.131.233 (Name is nonexistent or not a directory).   A Mac user in my group told me I first mount the location, but he didn't know how to do it.   Is it true and how do I do it? it seems my bash-completion got corrupted. Every time I try to use command substitution, for example when I type  ls $(ls Deskto&lt;Tab&gt;   ..result is..  ls $(ls Desktobash unexpected eof while looking for matching ")".   I tried removing my .bashrc file and cp /etc/skel/bashrc ~/ to get a new one. That works until I add something into my new bashrc. Even when I do echo '#" &gt;&gt; ./.bashrc it breaks again. Removing my bash_aliases did not help either.  Also sudo apt-get install --reinstall bash-completion did not do the trick.  However there are some threads about similar problem, nothing works.  ANY hint will be greatly appreciated! :) Solve the recurrence relation:$ T(n) = \sqrt{n} T \left(\sqrt n \right) + n$ $$T(n) = \sqrt{n} T \left(\sqrt n \right) + n$$  Master method does not apply here. Recursion tree goes a long way. Iteration method would be preferable.  The answer is $Θ (n \log \log n)$.  Can anyone arrive at the solution. I know that I can update a snap package using  sudo snap refresh &lt;package&gt;   But is there a way to update all snaps, like   sudo apt dist-upgrade With biblatex, alphabetic style, I have     &lt;author&gt;. &lt;title&gt;   But I want to have a colon ":" instead of the period "." after the author:     &lt;author&gt;: &lt;title&gt;   What do I have to change? Difference between shadowing and overriding in C#? Given $y_n=(1+\frac{1}{n})^{n+1}$ show that $\lbrace y_n \rbrace$ is a decreasing sequence Given  $$ y_n=\left(1+\frac{1}{n}\right)^{n+1}\hspace{-6mm},\qquad n \in \mathbb{N}, \quad n \geq 1. $$ Show that $\lbrace y_n \rbrace$ is a decreasing sequence. Anyone can help ?  I consider the ratio $\frac{y_{n+1}}{y_n}$ but I got stuck. I often find myself wishing SO supported drag and drop. For example I drag a tag to my favs and it would add it, or when searching by tag I would like to drag the tag to the search box and get [asp.net] added in the search box.   Does it make sense to add this feature or is it just too much work for so little use? How to create a custom Linux distro that runs just one program and nothing else? Another domain name pointing to my server IP? I was checking out my reverse-DNS entry of my domain the other day which is run from a dedicated server.   I noticed that another person/company had their domain pointing to my server? I have no idea who this company is or why they are pointing their domain at my server IP?  How can I go about stopping this or forcing them to change?