I've messed around with my network settings lately and I have no idea what I've done, but now my wifi doesn't seem to be working right. When I boot my system up I get the message      booting system without full network configuration   I tried following the guide  to reset my /etc/network/interfaces file, and now I get the same message at boot but my network manager doesn't even turn on when I login.  Any advice would be appreciated.
I was trying to solve internet problems, and seem to have made things worse: Now when I start the computer it gets stuck on "Booting system without full network configuration".   Does anyone know how to make it unstuck?   Alternatively: It got messed up when I changed the contents of /etc/network/interfaces, so presumably would work again if I changed it back. How can I edit this file during boot?   I'm using Ubuntu 12.10.
Sockets: Discover port availability using Java Things to focus on in a model lesson A model lesson is a usual element in interviews for the faculty level positions. Normally this is not a full lesson but a 15-minute version which is performed in absence of actual students for just a few professors from a hiring committee. It is supposed to demonstrate "your teaching style", but by design this is clearly a different enterprise: you should "act normal" doing "the same" things    in a different time-frame,  for a different audience,  with completely different motivation and  under exorbitant cost of failure.   Having said this, I also acknowledge the model lesson as indeed a much needed element of the interview, which helps to assess a candidate's set of relevant skills.  The question is how one can ideally prepare to give such a model lesson. Putting aside obvious things like "structure of the talk," "clear slides," "projection of the voice," and "body language", which normally should be already trained by experience, are there specific things that should be taken into account for the model lesson only? What about techniques like jokes, questions to the audience (e.g. how many of you are familiar with the definition of the derivative), work in pairs, which you probably use in a real classroom &mdash; is it a good idea to demonstrate them in a room full of senior professors? I am a little confused. How can I programmatically create a new cron job? I want to be able to programatically add a new cron job, what is the best way to do this?  From , it seems I could dump the current crontab and then append a new one, piping that back into crontab:  (crontab -l ; echo "0 * * * * wget -O - -q http://www.example.com/cron.php") | crontab -   Is there a better way? Midpoint-Convex and Continuous Implies Convex Given that $$f\left(\frac{x+y}{2}\right)\leqslant \frac{f(x)+f(y)}{2}~,$$ how can I show that $f$ is convex. Thanks.      Edit: I'm sorry for all the confusion. $f$ is assumed to be continuous on an interval $(a,b)$. How to boot from iso with Grub2/Burg boot loader How do I kill a process that won't die? I'm unable to kill a process using any of the techniques I'm aware of ("Force Quit" in Activity Monitor, top, killall from the Terminal) and wonder if there are some additional steps I can take.    ~ $ sudo killall -KILL 77439 Password: No matching processes were found ~ $ killall -KILL 77439 No matching processes belonging to you were found ~ $ killall 77439 No matching processes belonging to you were found ~ $ killall Mathematica No matching processes belonging to you were found   FWIW the process is "Mathematica" which I cannot relaunch, Quit, or Force Quit, or sample, either by name or PID, and it appears to have some odd side effects (screenshots don't appear, can't empty trash, and can't even shut down the system).  Are there additional steps that can be taken to really really kill a badly behaved process? I am trying to use the Directory.GetFiles() method to retrieve a list of files of multiple types, such as mp3's and jpg's.  I have tried both of the following with no luck:  Directory.GetFiles("C:\\path", "*.mp3|*.jpg", SearchOption.AllDirectories); Directory.GetFiles("C:\\path", "*.mp3;*.jpg", SearchOption.AllDirectories);   Is there a way to do this in one call? Does 10 heads in a row increase the chance of the next toss being a tail? I assume the following is true: assuming a fair coin, getting 10 heads in a row whilst tossing a coin does not increase the chance of the next coin toss being a tail, no matter what amount of probability and/or statistical jargon is tossed around (excuse the puns).   Assuming that is the case, my question is this: how the hell do I convince someone that is the case?   They are smart and educated but seem determined not to consider that I might be in the right on this (argument). Beamer, page/frame numbers, buttons and Appendix slides I can't open/ping any antivirus sites I have a problem with a virus in windows 7, I don't know what kind of virus is infected my OS, I installed kasersky antivirus, and clear all detected viruses. After that I can't open any antivirus sites, can't ping any antivirus sites. example:  C:\Windows\system32&gt;ping kaspersky.com Pinging kaspersky.com [38.117.98.231] with 32 bytes of data: General failure. General failure. General failure. General failure.  Ping statistics for 38.117.98.231:     Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),   When I ping to other sites, I get reply normally: example woth pinging to google.com  C:\Windows\system32&gt;ping google.com  Pinging google.com [31.7.160.224] with 32 bytes of data: Reply from 31.7.160.224: bytes=32 time=2ms TTL=61 Reply from 31.7.160.224: bytes=32 time=2ms TTL=61 Reply from 31.7.160.224: bytes=32 time=1ms TTL=61 Reply from 31.7.160.224: bytes=32 time=1ms TTL=61  Ping statistics for 31.7.160.224:     Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), Approximate round trip times in milli-seconds:     Minimum = 1ms, Maximum = 2ms, Average = 1ms   I tryed any antispyware/antimalware softwares, but null results.  Anyone else encountered this problem? Where does top command get all the data for CPU Utilization? Category-theoretic limit related to topological limit? Is there any connection between category-theoretic term 'limit' (=universal cone) over diagram, and topological term 'limit point' of a sequence, function, net...?  To be more precise, is there a category-theoretic setting of some non-trivial topological space such that these different concepts of term 'limit' somehow relate?  This question came to me after I saw (  ) a surprising fact that generalised metric spaces can be seen as categories enriched over preorder $([0,\infty],\leq)$. Ideal in a ring of continuous functions What is the rule for omitting/including the definite article in the following sentences:     I used to play piano.   I used to play the piano.   I would pick the first sentence, but I've heard people say the second sentence even when they are not referring to a specific piano. Which one is correct? Proof for alternative definition of the derivative I read somewhere recently that you can define the derivative as follows:  $$f'(x) = \lim_{h, k \to 0^+} \frac{f(x +h) - f(x - k)}{h + k}$$   I have been trying to prove this for about 2 hours, and can't seem to get it done. How should I proceed?  Edit: Assume $f$ is differentiable for all $x \in (x - \delta, x + \delta)$ for some $\delta &gt; 0$. How to make a file executable? How can I make my file so that I can double click on it, and it runs. It is a .sh script, but I also have files that say:  executable (application/x-executable)  in the description of what they are.  I can't run any of these from terminal, or by double clicking.  If possible, I would like a way using either the GUI or a Terminal, but not a combination of the two.  Here is a screenshot of what I see when I right click then go on properties. The file first:    And the shell script here:    NB: I accept that this is a duplicate (I was looking for it, and couldn't find it, so asked + answered it, hoping that I would find it) however, I don't think the question about .desktop files is a duplicate. I have this directory /foo/bar/. Inside, I have a python file named myfile.py. I made it executable by adding (at the top):  #!/usr/bin/env python   Then, I made it executable by issuing   chmod +x myfile.py   I edited my path by issuing  sudo nano /etc/paths   I added /foo/bar/ to it.  The problem is that although I can run myfile.py by typing ./myfile.py while I am inside /foo/bar/, it doesn't work from any other location. What am I doing wrong?  Thank you. How do you get the footer to stay at the bottom of a Web page? I have a simple 2-column layout with a footer that clears both the right and left div in my markup.  My problem is that I can't get the footer to stay at the bottom of the page in all browsers.  It works if the content pushes the footer down, but that's not always the case. I see a lot of questions comparing full frame (e.g EF for Canon, FX for Nikon) and crop lenses (e.g. EF-S for Canon, DX for Nikon) but I can't find the answer to what would be the differences between the photos taken with say a 50mm f/1.4 EF and EF-S lenses both used with   same APS-C sensor sized camera same ISO same f/1.4 f-stop same focal length same shutter speed   What would be the resulting differences in the photos? Which one would   be brighter than the other due the EF-S lens concentrating the light more? no that's wrong. Both put the same amount of light from the same FoV on the sensor. have greater depth-of-field? neither less problems towards the edges? generally the full frame more lens flare? generally the full frame lens unless there is, or you provide more shading anything else? not really, unless you start down the road of which one is typically of better build quality.   Edit: Added the answers from what seems to be the general consensus from the multiple answers and comments.  Results: My desire to buy a fast medium-high quality lens compatible with both full frame and crop camera's doesn't have to be hampered by the APS-C sensor size of my current camera.  This means I'm willing to part with more money to get a higher performance/quality lens as the performance/quality will be useful now and when I upgrade my camera.  Though reading reviews of some full frame lenses with short focal lengths, look out, as some are really only made to perform well on crop cameras even though they fit on a full frame camera and will give you a full frame picture, the edge quality is very bad. How do I go about tracking down IO usage in Linux and other *nix OS'? Occasionally, something on my system starts hammering the disk. I would like to log data that would let me know about I/O usage per process, then I could go back to it later and see what keeps doing this. How should I go about solving this problem? Bonus points for solving this for arbitrary block devices.