I'm logged into an Ubuntu 14.04 server remotely with ssh. I'm trying to find out which Desktop Environment is running.  When I do the following, nothing happens:  admin@server:~$ echo $DESKTOP_SESSION admin@server:~$ echo $XDG_CURRENT_SESSION admin@server:~$   I know for a fact that there is a desktop running on the server. I saw it this morning, but now I'm 5 miles away.
Is there any way (such as a command or environmental variable) to determine what window manager is the one actively running in the current session?
Calculating $\lim_{n\to\infty}\sqrt[n]{2^n-n^2}$ network manager says "device not managed" I used to be able to share my network connection by editing the Auto Eth0 to share with other computers in the Ipv4 section and now I upgraded my laptop to 11.10 .  Now are there no wired connections in the network manager. When I click my connections applet at the top of the tray it also says wired device not managed!  when I type ifconfig -a  daniella@daniella-1001HA:~$ ifconfig -a eth0      Link encap:Ethernet  HWaddr 90:e6:ba:83:d6:fc             UP BROADCAST MULTICAST  MTU:1500  Metric:1           RX packets:0 errors:0 dropped:0 overruns:0 frame:0           TX packets:0 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1000            RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)           Interrupt:45   eth0:avahi Link encap:Ethernet  HWaddr 90:e6:ba:83:d6:fc             inet addr:169.254.13.40  Bcast:169.254.255.255  Mask:255.255.0.0           UP BROADCAST MULTICAST  MTU:1500  Metric:1           Interrupt:45   lo        Link encap:Local Loopback             inet addr:127.0.0.1  Mask:255.0.0.0           inet6 addr: ::1/128 Scope:Host           UP LOOPBACK RUNNING  MTU:16436  Metric:1           RX packets:0 errors:0 dropped:0 overruns:0 frame:0           TX packets:0 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:0            RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)  wlan0     Link encap:Ethernet  HWaddr 00:25:d3:90:43:41             inet addr:192.168.0.6  Bcast:192.168.0.255  Mask:255.255.255.0           inet6 addr: fe80::225:d3ff:fe90:4341/64 Scope:Link           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1           RX packets:12881 errors:0 dropped:0 overruns:0 frame:0           TX packets:12867 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1000            RX bytes:8851081 (8.8 MB)  TX bytes:2343199 (2.3 MB) How to protect SHTML pages from crawlers/spiders/scrapers? I have A LOT of SHTML pages I want to protect from crawlers, spiders &amp; scrapers.   I understand the limitations of SSIs. An implementation of the following can be suggested in conjunction with any technology/technologies you wish:     The idea is that if you request too many pages too fast you're added to a blacklist for 24 hrs and shown a captcha instead of content, upon every page you request. If you enter the captcha correctly you've removed from the blacklist.   There is a whitelist so GoogleBot, etc. will never get blocked.   Which is the best/easiest way to implement this idea?  Server = IIS    Cleaning out the old tuples from a DB every 24 hrs is easily done so no need to explain that. I'm using the Webform module for Drupal 8. The module confirmation settings for a form are the following:   Page (redirects to new page and displays the confirmation message) Inline (reloads the current page and replaces the webform with the confirmation message.) Message (reloads the current page/form and displays the confirmation message at the top of the page.) URL (redirects to a custom path or URL) URL with message (redirects to a custom path or URL and displays the confirmation message at the top of the page.)   But how am I able to submit a form via AJAX so that the page doesn't reload on submit, but a confirmation message still replaces the form? What did I do wrong?    EDIT:  Here is the solution which works:  First you have to hook the form alter function and set an AJAX callback (as in ):  use \Drupal\Core\Form\FormStateInterface;  function MYTHEME_form_alter(&amp;$form, FormStateInterface $form_state, $form_id) {   if ( isset($form['#webform_id']) &amp;&amp; $form['#webform_id'] == 'MYWEBFORM' )   {     // add an AJAX callback to the form submission     $form['actions']['submit']['#ajax'] = array(       'callback' =&gt; '\Drupal\MYMODULE\Controller\DefaultController::processFormSubmission',       'event' =&gt; 'click',     );   } }   Then in the processFormSubmission function you can process the form (put use \Drupal\Core\Form\FormStateInterface; at the top of your file) like:  // Instantiate an AjaxResponse Object to return. $ajax_response = new \Drupal\Core\Ajax\AjaxResponse();  /* do sth */  // in the DOM: replace the form with the text 'form submitted' $ajax_response-&gt;addCommand(new \Drupal\Core\Ajax\HtmlCommand('#MYFORM', 'form submitted'));  return $ajax_response; Just looking for the difference between   2&gt;&amp;- 2&gt;/dev/null |&amp; &amp;&gt;/dev/null &gt;/dev/null 2&gt;&amp;1   and their portability with non-Bourne shells like tcsh, mksh, etc. Avoiding IF ELSE due to variable been NULL I can't destroy blocks in Minecraft Creative Mode (singleplayer) If a ring element is right-invertible, but not left-invertible, then it has infinitely many right-inverses. Number of planks required to stop the bullet Disk brakes severely reduced in power after replacing bearings I just installed Lyx 2.1 on my computer for the first time. I wanted to create my first trial pdf but switching to viewing mode is for some reason not working with the Acrobat Reader DC. I tried many options found on the web but I am afraid my little knowledge is not sufficing to make it work.  I would really appreciate a detailed answer :)   Thanks. What should I do when I have lenses with different filter thread sizes? ArcGIS Serious Application Error I'm a complete novice to GIS and just began an Introductory course. I am having an issue when I try to access the Symbology tab on a layer. Specifically, when I click on the 'Categories' field and 'Unique Values' subfield, ArcMap crashes and comes up with a report window to send to ESRI. The message is      ArcGIS for Desktop has encountered a serious application error and is   unable to continue.   What could be the problem? Cannot inherit from multiple classes defining __slots__? How do I update my TeX distribution? I'm trying to compile a document that only works with an up-to-date distribution, so I'd like to know: how do I update my distribution? Please provide screenshots where appropriate.  List of answers           To keep an eye on what’s going on at CTAN you may subscribe to the  or the RSS feed feed://www.mail-archive.com/ctan-ann@dante.de/maillist.xml Childrens fantasy, blind monk leading boy who can control the elements What is the best way to globally change the amount of vertical space between items in list environments? How to enable virtualization without using bios? I am using android studio.I want to run my app on simulator but it is asking me to install intel haxm,.When i install intel haxm it says that vitualization is not enabled/.To enable virtualization i need to goto bios but issue my bios is password protected &amp; i don't know password.So please tell me is there any other way by which i can enable the virtualization without going into bios? Soft Thresholding CUDA implementation multiple Open Drain UART over long distance I have 9 microcontrollers  and I have connected the RX and TX lines of 8 of them in parallel. My configuration is in master-slave. The master microcontroller send data to one of the 8 RX lines but only one of them can respond at a time. The cable length is about 3 to 5 metres between each node.  I have two questions. My test was done with 2 slaves instead of 8. UART at 9600bps.  If I setup the TX lines of the slaves as Open Drain it works fine, but the signal doesn't have steep ramps. I thought this happens due to Pull-up resistors. And I also think that is going to be better with 8 slaves on the bus, right?  Why doesn't that topology work if the TX lines of the slaves are not Open Drain?  I managed to make it work by disabling the transmit of the UART in all of them except one, and it worked fine. I had two slaves, so I disabled the one and left the other. Also I noticed that the edges of the signal was sharper. Why are they sharper in that case?  Regarding resistors: The value of the resistors for both RX and TX lines are 2.7KΩ. However the Open Drain topology would parallel the internal pull-up resistors. According to the datasheet that resistor is about 20KΩ at minimum. So, using a 2.7KΩ in the output would give us a total resistance of 2.52KΩ (20+2.7)/9. And the Open Drain would make a voltage divider 2.52KΩ + 2.7KΩ (Schematic 2). Which means with 8 slaves and Open Drain topology the signal will not go lower than 1V which is the threshold of the low level. Is that correct?  Wouldn't it be better to disable all the internal pull up resistors and place two (let's say: 4.7KΩ) only at the master side?  Distance: What is the maximum baud rate for such distance? I'm a little worried about the signal integrity. The test was done with 9600bps but I didn't notice any significant difference in 4800bps. The distortion of the signal didn't have a difference.  Voltage values are 3.3V for the UART bus.  Schematic 1. (all resistors are 2.7KΩ)        &ndash; Schematic created using   Schematic 2. (U4, U5, U6, U7, and U8 are omitted for simplicity).          EDIT: Thank you all very much about your answers so far. I wanted to point out that this is a question about UART only. I am not looking for alternative solutions. I'm just trying to find some answers about the above implementation.  EDIT2: Thank you very much for your answers! I ended up modifying a little my schematic. I disabled the internal pullup resistors of the microcontrollers and I placed external ones at the master's board. Their value would be around 1 KOhm to 3 KOhm. I have to do some tests more to decide the final value. I also replaced all series resistors with 130 Ohm.   I tested 5 slaves over 20 metre cable (with pullup 3 KOhm and 130 Ohm series resistors) and it worked fine.   Would it be better to add open drain/open collector line drivers on every TX lines?