I rebooted my system and receive a blank desktop after logging in. on getting into the shell with ctrl + alt + F1 and doing a "df" i see that my root partition is full with 100% usage.   I dont want to loose any data , how can i get my desktop back . Can someone please guide me through this.
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
Blender Nodes in Editor doesn't show preview Image I have a small problem with my blender lately. I want to make some compositing with my compositing nodes but the problem is, blender won't show me the preview Image. I have a Screenshot for you guys.    The preview Image itself is enabled, but it just won't show.  Thanks for your help in advance!  -Marten BM01 2011/12 Question 6 Geometry Problem Let $ABC$ be an acute-angled triangle. The feet of the altitudes from $A,B$ and $C$ are $D, E$ and $F$ respectively. Prove that $DE +DF \le BC$ and determine the triangles for which equality holds. The altitude from A is the line through A which is perpendicular to BC. The foot of this altitude is the point D where it meets BC. The other altitudes are similarly defined.   Thanks in advance for any contributions. In an  about The Force Awakens, the author suggests that:      Rey is Luke’s daughter.   I’ve missed any indicators of any such relationship while watching the movie.       For instance, I took neither Luke’s lightsaber calling out to Rey, nor her hug of consolation with General Organa as such. Is there any evidence that Luke is Rey’s father?    Is it known who Rey’s parents are? Where does the word "dog" come from? .NET How to check if path is a file and not a directory? I have a path and I need to determine if it is a directory or file.    Is this the best way to determine if the path is a file?  string file = @"C:\Test\foo.txt";  bool isFile = !System.IO.Directory.Exists(file) &amp;&amp;                           System.IO.File.Exists(file);   For a directory I would reverse the logic.  string directory = @"C:\Test";  bool isDirectory = System.IO.Directory.Exists(directory) &amp;&amp;                              !System.IO.File.Exists(directory);   If both don't exists that then I won't go do either branch.  So assume they both do exists. How do I show that $\ln(x) = \lim_{n\to\infty} n (x^{1/n} - 1)$?  I ran into this identity on . I haven't been able to find any proof online and my efforts to get from $\ln(x) := \int_1^x \frac{\mathrm dt}t$ to that limit have been a failure. Our production server (2012, VM + SAN) has 32 GB of RAM, the database size is ~80GB. The application uses TempDB heavily - disk is hit ~100 MBps both reads &amp; writes.  Seeing tons of SQL compilations/sec .. 95% of all batch requests are compilations.  Ideally would like to increase the RAM to 64GB or 128GB, but need to 'prove' to team that it's required.  Buffer Cache Hit Ratio (BCHR) is 99.9%, but Page Life Expectancy (PLE) is only ~400. What's the explanation for this ? I though PLE &amp; BCHR had a linear relationship (i.e. they increase or decrease together)  On other VMs with larger databases and lot more RAM, both BCHR &amp; PLE are high.  Current wait stats and perf counters This may be a silly question, but I ask it still. If I have declared a shebang  #!/bin/bash    in the beginning of my_shell_script.sh, so do I always have to invoke this script using bash  [my@comp]$bash my_shell_script.sh   or can I use e.g.  [my@comp]$sh my_shell_script.sh   and my script determines the running shell using the shebang? Is it the same happening with ksh shell? I'm using AIX. How to make a sound once a process is complete? I have started a long process through a terminal. Is it possible to make the Ubuntu terminal make a sound once the process is complete? This way, I don’t need to keep checking, but will instead be notified through a sound. How to block specific websites without using Parental Controls? Why can two (or more) electric field lines never cross? The the title is self explanatory, I guess.  Why can two (or more) electric  never cross? If $(X,\|\cdot\|)$ is a normed linear space, then how to show any ball $B(x,r)$ is convex? I know that if $x,y\in A\subset V$ then $[x,y]\subset A$, where $A$ is a convex subset of vector space $V$ and $[x,y]=\{(1-t)x+ty\mid 0\leq t \leq 1\}$. Please give me some hint.  I tried the following:  Claim. $[a,b] \subset B(x,r)$ Let $a,b \in B(x,r).$ Then I get $\|x-a\|&lt;r$ and $\|x-b\|&lt;r$.  Is it right? Difference between 2>&-, 2>/dev/null, |&, &>/dev/null and >/dev/null 2>&1 If my Schengen visa starts on the day of arrival which is one day ahead of departure, would they let me get into the plane? How do you prove that $\sum\limits_{n=0}^{\infty}{2n \choose n}x^n=(1-4x)^{-1/2}$? I tried to identify the sum as a binomial series, but the $4$ and the $-1/2$ puzzle me. (This series arises in studying the first passage time of a simple random walk.) Can't mount ISO file as loop device: Error: “failed to setup loop device” sudo mkdir -p /media/cdrom cd ~ sudo mount -o loop ubuntu-* / mount: ubuntu-*: failed to setup loop device: No such file or directory What is momentum really? Fuzzy graphics after upgrading to Ubuntu 20.04 I have recently upgraded Ubuntu 19.10 to latest LTS Ubuntu 20.04. After updating, I get serious artifacts on my screen. Every time I reboot (or log-in), my screen is fuzzy or scrambled (picture attached):     This is temporary. The fuzzy screen goes away when I change the background. But it reappears the moment I reboot or log back in.   I have Intel HD Graphics 520 (Skylake GT2).  The output of lspci -nn |grep -E 'VGA|Display' is:  00:02.0 VGA compatible controller [0300]: Intel Corporation Skylake GT2 [HD Graphics 520] [8086:1916] (rev 07)   Update:   On enabling Wayland in Ubuntu 20.04 and logging in to, these artifacts are however cured.   This is okay for now, but I am not sure about Wayland as I have not yet used it before.   Is there a way to correct the graphic issue with normal Ubuntu startup? How do I know if a laptop will work with Ubuntu? I want to buy a laptop at some point in the near future, but not knowing beforehand whether it works with Ubuntu makes the whole operation risky and tiresome. I would like to know if there is some kind of official hardware database where I can enter the name of the laptop I'm interested in and see if it's 100% compatible out of the box, or in case it isn't what is it exactly that doesn't work (ideally also if there is a way to fix it).  Does Canonical have a project along these lines? I'm attempting to get a better understanding of cryptography and have run into some questions about bcrypt.   Bcrypt relies on the blowfish cipher, which is a reversible method of encryption. But bcrypt is not reversible. How is that possible? Or am I mistaken? What does bcrypt do on top of blowfish to make it irreversible? Why does bcrypt use blowfish instead of twofish or threefish?