var directory showing its full via command 'df-h' df -h shows:  df -h Filesystem     Size    Used   Avail Capacity  Mounted on /dev/ada0p2    1.9G    256M    1.5G    14%    / devfs          1.0K    1.0K      0B   100%    /dev /dev/ada0p4    804G     34G    706G     5%    /usr /dev/ada0p5     93G    3.5G     82G     4%    /var   but, du -sh shows:  du -sh /var 3.5G    /var   Why? df is telling me i have no space out of the 93G but when i check the file size of the /var/ directory it amounts to 3.5G?  Can any one explain why this is please?
Why is df missing 500MB of available space? I've just had a message today from Ubuntu 11.04 that I have only 100 MB left, so I cleaned up some files, and I got 200 MB. Then, after a couple of hours, suddenly I have only 26 MB?! I tried df, du via mount --bind, /forcefsck with reboot - nothing could should what the culprit is - finally I searched big files, realized /var/log/syslog is 100MB+ and /var/log/kern.log is 200MB+ - blanked them with sudo bash -c 'echo &gt; ...' and rebooted, and now I have some spare MB.  But now, I realize I have another problem with df:  $ df -h Filesystem            Size  Used Avail Use% Mounted on /dev/sda5             9,7G  8,8G  385M  96% / none                  963M  696K  962M   1% /dev none                  969M   12K  969M   1% /dev/shm none                  969M  252K  969M   1% /var/run none                  969M     0  969M   0% /var/lock /dev/sda6             9,7G  8,1G  1,1G  89% /media/disk  $ df -h --block-size M Filesystem           1M-blocks      Used Available Use% Mounted on /dev/sda5                9845M     8960M      385M  96% / none                      963M        1M      962M   1% /dev none                      969M        1M      969M   1% /dev/shm none                      969M        1M      969M   1% /var/run none                      969M        0M      969M   0% /var/lock /dev/sda6                9845M     8235M     1110M  89% /media/disk   Note so for /, it says there are 9845M total; and Used 8960M - then remaining would be 9845-8960 = 885 M, however, here I have only 385M Available.  Also, for /media/disk, it says total 9845M, Used 8235M - then remaining would be 9845-8235 = 1610, however, here I have only 1110M Available.  In both cases, there is exactly 500 MB difference.  Where did this difference come from - and can I reclaim it?  Here is also lsof | grep 'deleted' - can't see nothing suspicious here:  $ lsof | grep 'deleted' nautilus  1911 user   21u      REG        8,5   142760     260562 /home/user/.local/share/gvfs-metadata/home (deleted) nautilus  1911 user   22w      REG        8,5    32768     268807 /home/user/.local/share/gvfs-metadata/home-fe882154.log (deleted) python    1919 user    8u      REG        8,5     4096     392258 /tmp/ffiqRK968 (deleted) python    2165 user    5w      REG        8,5        0     132261 /home/user/.[SNIP].lock (deleted) python    2166 user    5w      REG        8,5        0     132261 /home/user/.[SNIP].lock (deleted) python    2185 user   21r      REG        8,5   142760     260562 /home/user/.local/share/gvfs-metadata/home (deleted) python    2185 user   22r      REG        8,5    32768     268807 /home/user/.local/share/gvfs-metadata/home-fe882154.log (deleted) gnome-ter 2279 user   27u      REG        8,5      640     392575 /tmp/vte5KDX2X (deleted) gnome-ter 2279 user   28u      REG        8,5     4936     392605 /tmp/vteKRDX2X (deleted) gnome-ter 2279 user   29u      REG        8,5      648     392947 /tmp/vteMZDX2X (deleted) ubuntuone 2544 user   17u      REG        8,5     4096     392335 /tmp/ffiMErq0V (deleted) bamfdaemo 3235 user   12r      REG        8,5   143868     269077 /home/user/.local/share/gvfs-metadata/root (deleted) bamfdaemo 3235 user   13r      REG        8,5    32768     272310 /home/user/.local/share/gvfs-metadata/root-18092a02.log (deleted) firefox   5291 user   59u      REG        8,5    33288     132262 /var/tmp/etilqs_YdeZiWSd5iQwJ4U (deleted) firefox   5291 user   60w      REG        8,5    32768     132271 /var/tmp/etilqs_MNLXhEaEqoXMm9b (deleted) firefox   5291 user   70u      REG        8,5    34952     132297 /var/tmp/etilqs_yXDdwVeMxmmdpNz (deleted)
Hello can someone give me short tutorial how to:   Remove Windows 7 from my dual boot system (Ubuntu/Windows7) Let me use free space as new partition for data (so I don't need to extend Ubuntu itself here) Remove windows 7 option from boot screen   Update:  Thanks to Lekensteyn answer I successfully deleted windows. Now I created new partition (formatted to ext4), but I can not use it. I cannot copy files there, only as root.  Also when booting, Ubuntu complains it didn't find /windows partition (of course it didn't, I removed it). I feel like I should update some tables or what, any ideas? Can anonymous class implement interface? Is it possible to have an anonymous type implement an interface?  I've got a piece of code that I would like to work, but don't know how to do this.  I've had a couple of answers that either say no, or create a class that implements the interface construct new instances of that. This isn't really ideal, but I'm wondering if there is a mechanism to create a thin dynamic class on top of an interface which would make this simple.  public interface DummyInterface {     string A { get; }     string B { get; } }  public class DummySource {     public string A { get; set; }     public string C { get; set; }     public string D { get; set; } }  public class Test {     public void WillThisWork()     {         var source = new DummySource[0];         var values = from value in source                      select new                      {                          A = value.A,                          B = value.C + "_" + value.D                      };          DoSomethingWithDummyInterface(values);      }      public void DoSomethingWithDummyInterface(IEnumerable&lt;DummyInterface&gt; values)     {         foreach (var value in values)         {             Console.WriteLine("A = '{0}', B = '{1}'", value.A, value.B);         }     } }   I've found an article  that describes one approach. Is this the best way of doing this? I want to put a table and a figure side-by-side. The table should fill two third of the text width, and the figure the last third.  So I'd like to achieve one of the following effects (which are equivalent in my case):   One table with 3 columns. The first two columns contain text, the third column contains a lengthy image. The height of the image should be determined by the height of the whole table, if that's possible Or, a divided page like in newspapers. On the left side I have the table, on the right side the image.   What I have tried:  \begin{multicols}{2} \begin{tabular}{ l l } Text &amp; Text \\ Text &amp; Text \\ ... &amp; ... \\ \end{tabular} \vfill \begin{figure}[H]     \includegraphics[]{images/image} \end{figure} \end{multicols}   But this places the picture directly on top of the table.  I also tried using \usepackage[export]{adjustbox} and \includegraphics[right]{images/image} but the caption is still in the center of the page and therefor on top of the table. How can you check for a #hash in a URL using JavaScript? Entry to The US before 30-day grace period for student visa The F student visa allows me to enter the US up to 30 days before the program starts. For starting to set up things it is of my interest to arrive sooner than that. How hard is it to travel there beforehand with a tourist visa (waiver) and leave to, say Mexico, to then re enter on a proper date within the 30 days with the student visa? This seems easier than requesting for a status change inside the US from tourist to student.. Below is experimental data for the ratio $$R=\frac{\sigma(e^+e^-\rightarrow hadrons)}{\sigma(e^+e^-\rightarrow\mu^+\mu^-)}$$ as a function of the centre of mass energy $\sqrt s$. I am interested in the peak at around $100GeV$ which corresponds to the resonance of the $Z^0$ boson. There are two ways of looking at this that I have in mind:  We can effectively ignore the electromagnetic process around this energy, and so each process should have it's own Breit-Wigner peak centred on the mass energy of the $Z^0$. The ratio of these is just a constant. Thinking in terms of Feynman rules and again ignoring the electromagnetic process around this region, each process has the same propagator and vertex factors (roughly - ignore quark mixing) and there are some extra factors due to different quarks being possible and colour degeneracy, but still the ratio should be a constant (one possible issue here is interference between Feynman diagrams which I have neglected?).  So my question is why does the peak exist in the data? Proof that there must exist infinitely many solutions to a homogeneous system of equations when more unknowns than equations Why exactly does diffraction occur? Why do waves that were traveling in a straight direction change direction when passing through an opening?  I thought that the waves (red arrow) when colliding with the wall bounce in the opposite direction (green arrow).  And the waves that pass through the aperture follow its path normally as shown in the image on the right.   The waves that go in a straight direction should follow traveling straight line like a car that goes under a bridge the car is straight on the road. But this is not so.  Why does the direction of the waves change?  How is the direction of the waves calculated? Attack moving or Attack Canceling I watch streams sometimes and i see the high elo Ranged AD move between each shot. Do they gain anything with this? And if so whats a good way to practice it. Manga where the protagonist need to solve girl's quests A riddle about guessing hat colours (which is not among the commonly known ones) This is a riddle I heard recently, and my question is if someone happens to know the solution. I'm asking this out of curiosity more than anything else.  So here it is. The riddle is one of the countless variations of the "prisoners have to guess their hat colour" puzzle. $n$ prisoners are put a hat on top of their head, which can be red or blue. The colours are chosen at random by $n$ independent fair coin tosses. Then each prisoner can guess their own hat colour (red or blue) or pass. The prisoners can see each other, but not hear each other's calls and of course they have no other means of communication. This means that each call can only depend on the other prisoners' hat colours. However, before the distributing of hats begins, the prisoners are told the rules and can agree on a strategy. The prisoners win iff no prisoner guesses wrong and at least one prisoner guesses right. Which strategy should the prisoners use so that the winning probability becomes maximal?  Some remarks:   A simple strategy is that one player just guesses and all other players pass, so that the maximal probabilty is at least 1/2. For $n=2$ this strategy is optimal. For $n=3$, there is a strategy that wins in 6 out of 8 cases: When a player sees (red,red) he guesses blue, for (blue,blue) he guesses red, and otherwise he passes. More generally this shows that the maximal probability is at least 3/4 for $n\ge 3$. It's possible to show that any strategy fails for at least 2 hat colour configurations (unless $n=1$), which shows that the above strategy is optimal for $n=3$. For $n=4$ there are more than $10^{15}$ strategies, and for $n=5$ it's about $10^{38}$ strategies, making it quite infeasible to just use a brute-force computer program (maybe for $n=4$ it's possible when exploiting the obvious symmetries). When changing the rules slightly by forbidding players to pass, then the maximal winning probability is always 1/2. This is a nice little exercise.   Actually I heard the riddle only for $n=3$ and then thought about the general $n$. So it's entirely possible that there is no nice solution. Is it possible to browse the internet from a laptop so that the web sites you visit think you are browsing from a mobile device?  Say I need to connect via a very low bandwidth connection and just using the mobile version of the site is sufficient?  Currently I'm using Vista and Firefox 3.5 In Lubuntu, there's no 'Add New Program...' button in Desktop Session Settings. Is there an easy way to add new autostart programs in Lubuntu? How many arguments does a function require, and how to use that in `Manipulate` When trying to mount an exfat filesystem, I get the following error:  Error mounting /dev/sda6 at /media/gkp/Backup: Command-line  `mount -t "exfat" -o "uhelper=udisks2,nodev,nosuid" "/dev/sda6" "/media/gkp/Backup"'  exited with non-zero exit status 32: mount: unknown filesystem type 'exfat'   Exfat is used on some USB sticks and camera sd cards. What can I do to mount this type of filesystem? If an enemy is just below a 10-foot-high ceiling, are they in melee range of a creature on the ground? How to create a progress bar? When to use an offset in a Poisson regression? Does anybody know why offset in a Poisson regression is used? What do you achieve by this? How can I test for a player wearing specific armor? How can I test for a player that is wearing an iron helmet named "test1" and an iron chestplate named "test2" in Minecraft Version 1.12? Finding domain/range of a specific shader node input/output, inside the Blender UI? Is there anywhere within the Blender UI that displays the dimensionality &amp; bounding sets (e.g., all floats, floats in [0,1], floats in [0,255], etc) of arbitrary shader node inputs &amp; outputs?  I consistently find myself digging through stackexchange/the Blender docs/experimenting with less-than-equal-to to try to figure out what I need to divide by to normalize shader nodes' input/output values to within a specific range, or to center them at 0, etc. This seems like functionality that Blender's very rich UI might already have built into it, though, so I am wondering if I am just overlooking it somewhere.  As an example, I can do something like this, varying the threshold between 0, 0.5, and 1, and observing that in rendered view my sphere switches from all black to mixed black/white to all white, to convince myself that Blender's (Perlin) Noise Texture's Fac output naturally outputs floats in [0,1]:    But it seems odd that I should have to experiment, or search through docs or stackexchanges, to discover something like this. Is this information maybe already neatly displayed somewhere inside the Blender UI, and I just don't know where to look?