I have run into a situation where I'd like to get my wireless working without the benefit of a monitor, by sshing in.  I have KDE on the system, have enabled autologin for one of the users and would now like to set up the wireless to automatically connect without kwallet prompting me for a password.  (That way I can ditch my ethernet cable and move my computer out of the way).  I assume that this requires me to store the password in an unencrypted file; that's just fine with me.  I've run across some ways to do that via the gui () but, for my circumstances, I need to be able to pull this off via ssh.  Would anyone know how to accomplish this?  It would be much appreciated.
So basically, I'd like to use iwconfig to connect to my wifi network when I'm not inside X. But I just don't see a way to do it in the man page. Any idea?
How can I secure an Ethernet-over-power network? I just bought myself an Ethernet-over-power adapter, and plugged it in. It seems to be working great, but now I'm concerned that my neighbours may be able to access my network.  I live in a rowhome complex; is it possible they can access my network? If so, how can I secure it? How do I include lines in resolv.conf that won't get lost on reboot? I have finally migrated to 12.04 from 7.10. I have one last part to complete but I am stumped. I am using Puppet on each server, and in the past I have included a nameserver address and a search domain name for the puppetmaster in resolv.conf.   search puppetmaster.com nameserver 192.168.1.XXX   In 12.04 resolv.conf gets overwritten when rebooted. I cannot use a static IP for these, so using the /etc/network/interfaces to help me out is a nill point.  # Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8) #     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN nameserver 127.0.0.1   Is there a way to get resolvconf to handle this either in the head, tail or base? If there is, are there any examples I can use to tweak on my server.   Any help is much appreciated. How to add tags to files in Windows 7 so that they appear in search results In Windows 7, I want to add tags to my files (PDF, Word, Images etc) so that they appear directly in the search results, regardless of their content, title etc.    shows how to search by tag, but it does not tell how to add a tag in any file.  In the long term, I'm planning to add such tags programmatically as well. I use VirtualBox on my MBP and often need to mount my USB flash drive inside the guest.  The problem I'm running into is that the host OS (OS X Mavericks) immediately mounts the USB flash drive when I insert it.  When I try to unmount it (gracefully, through Finder), OS X complains that the device is in use.  Further research into lsof reveals that Spotlight and AVG are doing their thing with the flash drive.  Rather than fiddling with individual app settings, I'd like to just modify the host OS behavior so that the USB device doesn't auto-mount.  Any suggestions? Correlations between continuous and categorical (nominal) variables How do you clone a Git repository into a specific folder? Executing the command git clone git@github.com:whatever creates a directory in my current folder named whatever, and drops the contents of the Git repository into that folder:  /httpdocs/whatever/public   My problem is that I need the contents of the Git repository cloned into my current directory so that they appear in the proper location for the web server:  /httpdocs/public   I know how to move the files after I've cloned the repository, but this seems to break Git, and I'd like to be able to update just by calling git pull. How can I do this? The Node Editor won't work for the object selected What does `exec {STDIN}>&0` do? Prove $\csc(x)=\sum_{k=-\infty}^{\infty}\frac{(-1)^k}{x+k\pi}$ Ubuntu server shows me that I  use allmost all disk:  Usage of /:   95.5% of 118.12GB   And I try to find big folders and files, run ncdu:  ncdu 1.8 ~ Use the arrow keys to navigate, press ? for help                                                                                                                                                  --- / ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------     5.5GiB [##########] /root                                                                                                                                                                                    2.3GiB [####      ] /var   628.6MiB [#         ] /usr   209.9MiB [          ] /lib    28.2MiB [          ] /boot     8.6MiB [          ] /bin     7.7MiB [          ] /sbin     6.6MiB [          ] /etc   208.0KiB [          ] /run   112.0KiB [          ] /tmp    48.0KiB [          ] /opt e  16.0KiB [          ] /lost+found     8.0KiB [          ] /dev     8.0KiB [          ] /media     4.0KiB [          ] /lib64 e   4.0KiB [          ] /srv e   4.0KiB [          ] /selinux e   4.0KiB [          ] /mnt e   4.0KiB [          ] /home     0.0  B [          ] /proc     0.0  B [          ] /sys @   0.0  B [          ]  initrd.img @   0.0  B [          ]  vmlinuz   According to ncdu I use about 10 GiB of 128 GiB - it is about 10 %. Contradiction.  How to clean my ubutntu server without rebooting?  I thought that ncdu lies and used another apps to find big files and folders. All of them shows the same result as ncdu.  And df -h command shows that disk is full.  # df -h Filesystem      Size  Used Avail Use% Mounted on /dev/xvda       119G  113G     0 100% / udev            2.0G  8.0K  2.0G   1% /dev tmpfs           788M  212K  788M   1% /run none            5.0M     0  5.0M   0% /run/lock none            2.0G     0  2.0G   0% /run/shm   Update  sudo du -sch /* result:  /# sudo du -sch /* 8.7M    /bin 29M /boot 8.0K    /dev 6.6M    /etc 4.0K    /home 0   /initrd.img 210M    /lib 4.0K    /lib64 16K /lost+found 8.0K    /media 4.0K    /mnt 48K /opt du: cannot access `/proc/4470/task/4470/fd/4': No such file or directory du: cannot access `/proc/4470/task/4470/fdinfo/4': No such file or directory du: cannot access `/proc/4470/fd/4': No such file or directory du: cannot access `/proc/4470/fdinfo/4': No such file or directory 0   /proc 5.0G    /root 212K    /run 7.8M    /sbin 4.0K    /selinux 4.0K    /srv 0   /sys 112K    /tmp 629M    /usr 2.3G    /var 0   /vmlinuz 8.1G    total   8.1G  total as usual. But I see cannot access rows, maybe problem because of them.  Then I checked the biggest folder in /. It is /root :  /# sudo du -sch /root/* 96K /root/Downloads 2.5G    /root/Dropbox 36K /root/nohup.out 4.0K    /root/npm-debug.log 4.0K    /root/readonly 980K    /root/redis-2.6.16.tar.gz 228M    /root/tmp 2.7G    total How did Ron speak Parseltongue and re-enter the Chamber of Secrets? Although 'The Deathly Hallows' was overall an excellent conclusion to Harry Potter's saga, there were moments within the book that felt infuriatingly lazy, like Rowling was whipping the plot along regardless of the holes she tore in it. For me, the lowest point was when Ron gargles at the entrance of the Chamber of Secrets- and succeeds!- so he can get some Basilisk fangs to destroy a Horcrux (which are conveniently vulnerable to this venom).  This is, by itself, a shockingly slapdash deus ex machina, but even worse is how it is completely inconsistent with the guidelines Rowling herself set. First and foremost, Parseltongue is not just a language, but a magical ability that can only be learned through hereditary or magical means (Potter being the sole example of the latter). This is firmly established by the fact that even Dumbledore, the greatest wizard of all time and a polyglot, is completely unable to speak it despite understanding it perfectly.  Without linguistic knowledge nor inherent ability, the chances of making any kind of coherent sentence (let alone the right one!) would be incredibly slim even in the case of mundane languages; it would be like gibbering at a Filipino in the hope that what you said was fluent Tagalog and didn't insult their mother.  Other baffling issues somewhat related to my question are thus; even if Ron had somehow unlocked the gate, how did he make his way down? In the second novel, Lockheart's foolery demolished the main tunnel to the Chamber, making it impossible to access or leave; the fact that the teeth are still there also implies that the Chamber wasn't excavated and the rubble cleared in the interval. Granted, he could have tried Apparating, but then he wouldn't have needed to fake Parseltongue to begin with. Does Hilbert's $\varepsilon$-calculus have any real problem when using for incomplete systems? What is the maximum number of people that will join a settlement? I've got two settlements on the go that I'm paying attention to - Sanctuary and the Starlight Drive In. Both of these settlements have radio towers and beds and all resources in the green however they appear to have stopped growing at 10 people in each settlement even though happiness is above 80 and I've got 15+ beds at each location.  What is the maximum number of people that will join a settlement? Proof that $ p $ | ${ p^n \choose k } $ for any prime $p$ and $ k < p^n$ I know how to prove the fact that $ p$ | ${ p \choose k } $ (when writing it as a fraction, $p$ cannot be divided by any of the $1\times2\times...\times k$ or $1\times2\times...\times(p-k)$ because $p$ is prime).  When I try to apply the same rationale for $ p$ | ${ p^n \choose k } $ I get stumped because $p^n$ is in fact divisible by one of the $k! = 1\times2\times...\times k$, where $0 &lt; k &lt; p^n$.  If we take the example of $2^3$ and $k = 7$, we can easily see that $k! = 1 \times 2 \times ... \times 6 \times 7$, and $2$ clearly divides $2^3$.  How else can I approach this? Enable thumbnail preview when uploading files in Google Chrome/Firefox? I have google chrome and when I upload photos to Facebook or Imageshack I cannot find a way to show thumbnails, only detail view. I also tried this in Firefox. This is quite important as it is stopping my friend from switching to Ubuntu over Windows.  Included a picture of the File Upload window, how do I  change this to a thumbnail view rather than the current list? For some reasons, homomorphism is a very hard area for me to make improvements. I've been hitting the brick wall for almost 2 hours.   Prove that no homomorphism exists from $Z_{16}\oplus Z_2$ onto $Z_4\oplus Z_4$.  Assume a homomorphism $\phi$ exists from $Z_{16}\oplus Z_2$ onto $Z_4\oplus Z_4$. Then $\phi$ is an isomorphism.  Note that the $\left | \ker \phi \right |=2$ The $\ker \phi$ is also a normal subgroup for $Z_{16}\oplus Z_{2}$. We want possible normal subgroup of order 2. I.e., 2 elements in each normal subgroups.  By Lagrange's theorem, the order of each element in a group divides the order of a group so the possible order of the elements are 1 or 2. If the elements has order 1, then the Ker \phi cannot have 2 elements.  Hence, $\ker\phi$ = $\left \{ (0,0),(8,0) \right \}$ ,$\left \{ (0,0),(0,8) \right \}$,$\left \{ (0,0),(8,1) \right \}$, possibly.  By the First isomorphism theorem:  $\phi: Z_{16}\oplus Z_2 \rightarrow Z_2\oplus Z_2$  $\Psi: G/\ker \phi \rightarrow \phi\left ( Z_16\oplus Z_2 \right )=Z_2\oplus Z_2$  $g\ker \phi  \mapsto \phi(g)=\Psi(g\ker \phi)$  Any help is appreciated.  Edit: I know that $(2,0)$ has order $8$ in $Z_{16}\oplus Z_{2}$ but any elements in $Z_{4}\oplus Z_{4}$ does not have order $8$ which would have solved the question at the outset. But I would like a different route. Lower bound on energy is potential minimum Suppose we have a particle of mass $m$ that is in an eigenstate $|\psi\rangle$ of the Hamiltonian $\hat{H}=\hat{T}+\hat{V}$, where $\hat{T}$ is the kinetic energy operator and $\hat{V}=V(\hat{r})$ is the potential energy operator. If the potential has lower bound $V_0$, then is it necessary for the energy eigenvalue $E$ of $|\psi\rangle$ to be greater than $V_0$? Classically this is true, since we regard negative kinetic energy as physically unrealizable/meaningless. However, I don't know if I can necessarily say the same in the quantum case. For example, what I'm tempted to do is write  $$\langle\psi | \hat{T}|\psi \rangle = \langle\psi | E-\hat{V}|\psi\rangle$$  and say "If $E&lt;V_0$, then the RHS is necessarily negative, implying the LHS is as well, which we will regard as physically meaningless. If $E=V_0$, then $|\psi\rangle$ is trivial.", but I'm not sure if that's right.   Confused by that, I then wanted to show that, if $E&lt; V_0$, then a non-trivial $|\psi\rangle$ is non-normalizable. However, I'm not entirely sure how to do this. Why don't metals glow from red to yellow to green to blue etc.? Why only red, then yellow and then white? Shouldn't all wavelengths be emitted one by one as the temperature of the metal increases?   If some metals do glow at with different colours, could you give me examples of such metals and the reason why this happens in specific cases? I am using different operating systems on different machines on different locations. I am using a USB flash disk to keep my files (source codes etc.).  I am new to Mac OS X and now I realize there are lots of files created with a dot underscore ._ prefix.  Questions  Why are ._ files created?   What are their purpose?   How can I avoid them? Electric charge is lorentz invariant I know that electric charge is lorentz invariant quantity and I can easily think of experiment to check that. Is a though experiment that can prove that also?