I can't install a new kernel because by boot partition is full. However I also can't remove an old kernel:  sudo apt-get purge -f  linux-image-3.2.0-29-generic-pae [.. reading package lists etc, standard stuff, not relevant &amp; was too lazy to translate it] The following packages have unmet dependencies:  linux-image-generic-pae : depends on: linux-image-3.2.0-41-generic-pae but shall not be installed E: unmet dependencies. try »apt-get -f install« without giving a package name (or give a solution).   Any idea how I can fix this? Thanks :-)  (Note: apt-get -f install also fails: not enough free space!)
My first issue was when I tried to apt-get update or apt-get upgrade. On upgrade I get the following error:  You might want to run 'apt-get -f install' to correct these. The following packages have unmet dependencies: linux-image-server : Depends: linux-image-3.2.0-27-generic but it is not installed E: Unmet dependencies. Try using -f.   I tried running apt-get install -f and this was the output(after saying yes on prompt)  (Reading database ... 186183 files and directories currently installed.) Unpacking linux-image-3.2.0-27-generic (from .../linux-image-3.2.0-27-generic_3.2.0-27.43_amd64.deb) ... Done. dpkg: error processing /var/cache/apt/archives/linux-image-3.2.0-27-generic_3.2.0-27.43_amd64.deb (--unpack):  failed in write on buffer copy for backend dpkg-deb during `./boot/System.map-3.2.0-27-generic': No space left on device  No apport report written because the error message indicates a disk full error                                                                           dpkg-deb:    error: subprocess paste was killed by signal (Broken pipe) Examining /etc/kernel/postrm.d . run-parts: executing /etc/kernel/postrm.d/initramfs-tools 3.2.0-27-generic   /boot/vmlinuz-3.2.0-27-generic run-parts: executing /etc/kernel/postrm.d/zz-update-grub 3.2.0-27-generic /boot/vmlinuz-3.2.0-27-generic Errors were encountered while processing: /var/cache/apt/archives/linux-image-3.2.0-27-generic_3.2.0-27.43_amd64.deb E: Sub-process /usr/bin/dpkg returned an error code (1)   I tried running apt-get autoremove and it gives me the same error as apt-get upgrade.  When I run df, I get this for /boot:  /dev/sda1                    233191     230297         0 100% /boot   So, I read elsewhere that I should try to purge old kernels. I checked for what kernels I had with:  $ dpkg -l linux-image-\* | grep ^ii ii  linux-image-2.6.38-13-server  2.6.38-13.52  Linux kernel image for version 2.6.38 on x86_64 ii  linux-image-3.0.0-13-server   3.0.0-13.22   Linux kernel image for version 3.0.0  on x86_64 ii  linux-image-3.0.0-14-server   3.0.0-14.23   Linux kernel image for version 3.0.0  on x86_64 ii  linux-image-3.0.0-15-server   3.0.0-15.26   Linux kernel image for version 3.0.0  on x86_64 ii  linux-image-3.0.0-16-server   3.0.0-16.29   Linux kernel image for version 3.0.0  on x86_64 ii  linux-image-3.0.0-17-server   3.0.0-17.30   Linux kernel image for version 3.0.0  on x86_64 ii  linux-image-3.2.0-24-generic  3.2.0-24.39   Linux kernel image for version 3.2.0  on 64 bit x86 SMP ii  linux-image-3.2.0-25-generic  3.2.0-25.40   Linux kernel image for version 3.2.0  on 64 bit x86 SMP ii  linux-image-3.2.0-26-generic  3.2.0-26.41   Linux kernel image for version 3.2.0  on 64 bit x86 SMP   When I try to remove the oldest with this:  $ sudo apt-get purge linux-image-2.6.38-13-server Reading package lists... Done Building dependency tree Reading state information... Done You might want to run 'apt-get -f install' to correct these: The following packages have unmet dependencies: linux-image-server : Depends: linux-image-3.2.0-27-generic but it is not going to be     installed E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).   How can I free up or extend boot without messing up my installation?
Disable output buffering Is output buffering enabled by default in Python's interpreter for sys.stdout?  If the answer is positive, what are all the ways to disable it?  Suggestions so far:   Use the -u command line switch Wrap sys.stdout in an object that flushes after every write Set PYTHONUNBUFFERED env var sys.stdout = os.fdopen(sys.stdout.fileno(), 'w', 0)   Is there any other way to set some global flag in sys/sys.stdout programmatically during execution? How to reset the Xorg / xserver? Xserver keeps crashing on my general user account both in Unity 3D and 2D. It doesn't do it on the guest account.  That's why I want to reset / rollback everything xserver related, hoping this is going to fix it.  Most answers on this involve sudo dpkg-reconfigure xserver-xorg. However, this does nothing for me (generates no output) and I read in other forums, that it's deprecated.  So, what's the current way to reset all xserver / xorg options; what's the alternative to sudo dpkg-reconfigure xserver-xorg? X crashes during work, not before login or so. And the effect of a crash is, that I get thrown out of the session, not a freeze or machine crash. Can you raise a number to an irrational exponent? Windows 8 Setting an image on the login screen In Windows 8.1 when you log in there's the prelogin screen that has an image you can change, but then there's also the login (password entry) screen that as far as I can see is just a solid color.  How could I replace that with an actual picture? (ie, if I wanted a company logo to be displayed in the large space underneath the password entry box. This is a  about RAID levels.    What are:   the RAID levels typically used (including the RAID-Z family)?  deployments are they commonly found in? benefits and pitfalls of each? Reoccurring Bent Axles, any reasons or upgrades? Earlier this month I had a issue with a broken axle.  It was the original that was sold with the bike and lasted around 5,000 miles.  I went to my LBS and bought a new axle (unbranded, labeled, etc, paid $13, came with cones, spacers, and hardware).  I did the install myself and had everything adjusted nicely.  The next time I rode it was on my commute to work, but I didn't get 4 miles into it when I found that I bent the axle.    I took the wheel to the shop but they wouldn't do anything about it since I didn't have them do the work.  However, I figured this was a fluke and asked them for a new axle and to true the wheel.  Once again I did the install of the axle and only got 15 miles out of it this time before bending it.  Before I got home I felt the wheel get stiff, but it stayed true.  The question is what will be a cause of bending 2 axles in 20 miles?    I think the guy at the shop said it was a cro-moly axle (while talking to another person today at the shop, these may not be), and he couldn't believe that I bent it.  If so, where would such an axle fall in the quality hierarchy?  Or is my hub toast?  While the wheel was being repaired, I swapped to a new original wheel for about 2 weeks.  I have not had any issues with it, but I wanted to keep it as new as possible.   Reading other questions I saw a comment that said not to use a hub where the bearing was catching.  I did have one in this wheel but I figured since it is a cheap wheel I would just burn it up and move on to a better one.  Besides, it has lasted 5k miles without issue to this point.  The bike in question is a 2008 Schwinn High Timber with Joytech freewheel hubs.  I do use a trailer with this bike using a Burley axle hitch.  While I had the hitch installed on both axles I bent, I did not have either trailer hooked up to them.  Something I would like to note is that when I removed the first bent axle (axle #2) that the cones on it had a wavy bearing track.  I didn't think too much of it, and I put them on axle #3.  Only having a few miles on them shouldn't have made a difference? Is the empty set a group? I know that a set G with a binary operation $*$ is a group, if:   $a*b\in G$, for all $a, b \in G$. $*$ is associative:   $$(a*b)*c=a*(b*c) \\ \text{for all }a, b, c\in G.$$   An identity element $e \in G$ exists, such that   $$a*e = e*a = a\\ \text{for all }a\in G.$$   For all elements $a \in G$, there exists an $a^{-1} \in G$, such that:   $$a*a^{-1} = a^{-1}*a=e.$$  Can I use that to show that the empty set is a group? Stochastic processes book suggestions. I would like to find a book that introduces me gently to the subject of stochastic processes without sacrificing mathematical rigor. It would be great if the book has lots of examples and that the book is designed for undergraduates. Just like how there are rigorous undergraduate abstract algebra books (I am thinking of GAllian's contemporary modern algebra here).   I already studied measure theory, and prob. theory.  Thank you. Moon photography Hi I am a photography hoobyist. At the moment I am using a Nikon D3100 with the standard kit lens (18-55mm). I am interested in taking photos of the moon. I am debating whether to buy a 55-200mm lens or a 55-300mm lens. Which one would be better?  P.S I am on a tight budget and I am looking for a lens for personal use, not commercial.  Would appreciate any answers!  Thank you! I would like to search an entire MS SQL 2000 database for one value. This would be to aid development only. Keep that in mind when considering this question.   This will get all the table names and the column of the data type I'm looking for:  SELECT Columns.COLUMN_NAME, tables.TABLE_NAME FROM INFORMATION_SCHEMA.Columns as Columns  JOIN INFORMATION_SCHEMA.TABLES as tables  On Columns.TABLE_NAME = tables.TABLE_NAME WHERE Columns.DATA_TYPE = 'INT'     I was thinking something like this:  -- Vars DECLARE @COUNTER INT DECLARE @TOTAL INT DECLARE @TABLE CHAR(128) DECLARE @COLUMN CHAR(128) DECLARE @COLUMNTYPE CHAR(128) DECLARE @COLUMNVALUE INT  -- What we are looking for SET @COLUMNTYPE = 'INT' SET @COLUMNVALUE = 3 SET @COUNTER = 0  -- Find out how many possible columns exist SELECT @TOTAL = COUNT(*)   FROM INFORMATION_SCHEMA.Columns as Columns  JOIN INFORMATION_SCHEMA.TABLES as tables  On Columns.TABLE_NAME = tables.TABLE_NAME WHERE Columns.DATA_TYPE = @COLUMNTYPE PRINT CAST(@TOTAL AS CHAR) + 'possible columns' WHILE @COUNTER &lt; @TOTAL BEGIN     SET @COUNTER = @COUNTER +1     -- ADD MAGIC HERE END   Any ideas?  UPDATE I recently found this  that works quite well. Can't do comparison on PageReference In my page constructor I call a method isFirstPageLoaded, to  check if the loaded page is the first page of the wizard.   private final PageReference FIRSTPAGE = Page.Maintenance_Lock_1;   private void isFirstPageLoaded() {          if(ApexPages.currentPage()!=this.FIRSTPAGE) {              throw new MaintenanceLockException(this.FIRSTPAGE + ' --- ' + ApexPages.currentPage());          }      }   The problem is: Even if I open the first page of the wizard, the exception is thrown. How can I compare two PageReferences? I would like to avoid to parse the URLs and remove parameters etc... is there an easy way or photoshop plugin to distribute words in evenly spaced formation No module named numpy I am trying to run Jupyter notebook from my Ubuntu subsystem in Windows 10. I've installed numpy, scipy, and pandas using the following commands:  pip install scipy numpy pip install pandas   When I load python in Ubuntu, there is no issue importing numpy in Ubuntu cmd.   But, when I run my Jupyter Notebook from Ubuntu terminal, and try to import numpy as np, or import pandas as pd, they report  ModuleNotFoundError                       Traceback (most recent call last) &lt;ipython-input-1-a9340201ed9f&gt; in &lt;module&gt;       5 import dash_html_components as html       6 import plotly.graph_objs as go ----&gt; 7 import numpy as np       8 from dash.dependencies import Input, Output       9   ModuleNotFoundError: No module named 'numpy'   Is there anyway to solve this issue? Thanks a lot. Prove the inequality $n! \geq 2^n$ by induction I'm having difficulty solving an exercise in my course.  The question is:      Prove that $n!\geq 2^n$.   We have to do this by induction. I started like this:   The lowest natural number where the assumption is correct is $4$ as: $4! \geq 2^4 \iff 24 \ge 16$. The assumption is: $n! \ge 2^n$.   Now proof for $(n+1)$ which brings me to: $(n+1)! \ge 2^{(n+1)}$  I think I can rewrite it somehow like this:  $$ {(n+1)} \times {n!}  \stackrel{\text{(definition of factorial)}}{\ge} 2^n \times 2 $$  $$ (n+1) \times 2^n \ge 2^n \times 2 $$  Then I think I can eliminate the $2^n$ and have something like this: $n+1 \ge 2$, or $n \ge 1$.  But I think I'm wrong here some where and was hoping somebody has some advice on this. How can I prove the above assumption?  Any help would be appreciated, kind regards. I'm new to Ubuntu. What's the application extension for development reasons? I know Windows is mainly .exe and Mac is .dmg or .app. Does Linux have an unique one? I am a new user, who has just been told to run / execute a command. The answer has some text with a grey background like this text here or  sometimes this text here.   However, I don't know what "run" or "command" means in relation to Ubuntu.  How do I do this?    This is intended for use as a Q&amp;A you can link to when you tell someone to run a command. Why do we use encrypt-decrypt-encrypt (EDE) in 3DES, rather than encrypting three times? I'm wondering why we use encrypt-decrypt-encrypt (EDE) sequence in 3DES (also known as DES-EDE, TDES or TDEA) with three keys instead of three times encryption (EEE) with three different keys? Set of limit points of a subset of a Hausdorff space is closed. Let $X$ be a Hausdorff space and $A\subset X$.  Define $A'=\{x\in X\mid x\text{ is a limit point of }A\}$.  Prove that $A'$ is closed in $X$.  Relevant information:  (1.) Every neighborhood of a point $x\in A'$ contains a point $y\in A'$ distinct from $x$ (in fact, in a Hausdorff space, every neighborhood of $x$ contains $\infty$-many points of $A$ distinct from $x$)  (2.) In a Hausdorff space, every sequence has a unique limit.  On first glance, it should be an easy proof, but I've made little progress.  I was planning on showing $\overline{A'}=A'$.  Firstly, $A'\subset \overline{A'}$ trivially.  To show $\overline{A'}\subset A'$, proceed by contradiction.  Assume there exists $x\in\overline{A'}$ such that $x\not\in A'$.  This should yield an easy contradiction but I don't see it.  In particular, I'm unsure if the fact that $x\in\overline{A'}$ implies that there actually exists a sequence in $A'$ converging to $x$.  By (2) we know all sequences have unique limits, but do we know that elements in the closure are limits of sequences?  If this is true, it should yield an easy contradiction.  Any help? I have seen several times on TV documentaries where the presenter is taken to something like a library archive, and shown a book which they proceed to read an excerpt from.  On a couple of occasions the camera has shown the text they were reading and generally I have thought that I would struggle to read the words because of how the letters were formed (e.g. , or ).  This got me to wondering about how pronunciation and sentence formation may have changed over time as well, and how far back in time could I travel and still be understood while speaking my "modern" English in England (while obviously not talking about modern concepts like mobile phones or space travel)? If verification is quality control, what is a validation?