Problems installing Sagemath – Ask Ubuntu

In Ubuntu 20.04, when I type:

sudo apt-get install sagemath sagemath-jupyter sagemath-doc-en

I get:

”Package sagemath is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source.

E: Package ‘sagemath’ has no installation candidate
E: Unable to locate package sagemath-jupyter
E: Unable to locate package sagemath-doc-en”

It appears the PPA is no longer maintained. Am I forced to go through the hassle of getting the binary and then all its dependencies or am I missing something obvious? I feel dumb.

virtualbox – Installing Unity Using The Mini ISO

I am using VirtualBox, and I am trying to install Unity as said in this link. I am able to install Ubuntu Mini, and get the tty. I am not able to proceed further, when I do

sudo apt install ubuntu-unity-desktop

I tried (as per the feedback from the terminal)

sudo apt install ubuntu-unity-desktop --fix-missing

I am getting hundreds of error messages like

Failed to fetch, cannot initiate connection, network is unreachable (IP 80).


My Internet connection is perfectly OK on the host machine. How to fix this?

system installation – Installing ubuntu taking too long

im trying to install ubuntu on my 32 gb 2.0 usb sand disk pendrive which is taking like 6-8 hours on minimal settings like minimum apps and no internet connected.
When i tried installing on my 16 gb class 10 sd card its taking the normal 20 mins(but i can’t use it as my laptop cannot boot from sd, only usb).
So is this because 2.0 usb speed is so slow for installation, or is there any other issue ?

Termux – help to installing the boostrap packages

Termux is say unable to install the bootstrap packages in itel 1516 plus pls help me.

mac – Is installing Windows on Macbook Pro for Game development good and efficient

If you look at it objectively, then yes installing Windows in BootCamp is both “good” and “efficient” in the sense that (a) this is a supported configuration for your computer that will not “break” anything, and (b) you’ll be able to make full use of the computer’s hardware’s performance.

On the other hand, I don’t see you couldn’t keep using macOS for game development as well. There’s no rule or general recommendation that Windows is always “best for game development” – far from it.

If you’re planning to develop a game for the Mac or for iOS users, I would stick with the Mac. If you’re developing a game only for Windows users, there’s good arguments for running on the same target as your own users.

big sur – Installing NVIDIA Visual Profiler (NVVP) on Big Sur

I am trying to install NVIDIA Visual Profiler (NVVP) on my macbook with Big Sur v11.2.1.
I downloaded NVVP from here and OpenJDK from here.

I am getting the following error:

bash-3.2$ ./nvvp -vm /Library/Java/JavaVirtualMachines/adoptopenjdk-11.jdk/Contents/Home/bin/
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by (file:/Applications/nvvp/libnvvp/plugins/org.eclipse.osgi_3.10.1.v20140909-1633.jar) to method
WARNING: Please consider reporting this to the maintainers of
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release

If I just run ./nvvp with -jvm parameter, the workspace selection window pops up but it is not clickable at all.

Any kind of help is appreciated!

server – Installing packge on docker container


  • Raspberry pi 4: arm64/v8
  • Ubuntu 20.04 LTS

I am having trouble installing a chromedriver on arm64 architecture. From research it seems chromedriver is not officially supported on arm64 so I have found this package from launchpad.

When I install it locally it seems to fetch the package fine however when I try to run it from my docker container it says it cannot find the package.


FROM arm64v8/python:3.6

# set display port to avoid crash

RUN apt-get update

RUN apt-get install chromium-browser

# needed files for pyodbc
RUN apt-get install gcc libc-dev g++ libffi-dev libxml2 libffi-dev unixodbc-dev -y



COPY requirements.txt requirements.txt
RUN pip3 install -r requirements.txt

COPY . .
CMD ["python", ""]

Here is the error I get when doing docker-compose up -d

Package chromium-browser is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'chromium-browser' has no installation candidate
The command '/bin/sh -c apt-get install chromium-browser' returned a non-zero code: 100
ERROR: Service 'backend' failed to build : Build failed

Do I need to add the repository? I am a complete noob at linux/docker.

centos – Installing GridDB on a VM hosted on Azure

So I’ve been trying to work with GridDB on a CentOS VM with no success. I have my VM hosted on Azure and it’s CentOS 8. I’m following the steps laid out on this guide. After using wget to download the rpm package I try to install but I keep getting failed dependency errors as follows:

    Failed dependencies:    
     /usr/bin/python is needed by griddb_nosql-4.2.0-1.linux.x86_64 is needed by griddb_nosql-4.2.0-1.linux.x86_64 is needed by griddb_nosql-4.2.0-1.linux.x86_64  is needed by griddb_nosql-4.2.0-1.linux.x86_64 is needed by griddb_nosql-4.2.0-1.linux.x86_64

The thing is, I have python installed and correctly configured so I do not understand why it would not run.

server – Installing Ubuntu 20.04.2 Live ISO on a Dell R730 with Perc Raid controller

It always blows up during the install. configuring installed system

   running '/snap/bin/subiquity.sub
   running '/snap/bin/subiquity.sub
   curtin command apt-config
   curtin command in-target

I did F10 on boot and install Other OS via the Lifecycle controller

Any ideas?

Terminal on Ubuntu20 does not start anymore after installing Python 3.7

looks I have chicken and egg problem. I have updated Python3 to 3.7 on Ubuntu 20.04
The terminal does not start anymore. I have read this thread: Terminal not opening up after upgrading python to 3.7

Question is: how do I open a terminal (this is my problem) to configure gnome-terminal to fix the problem as suggested there?
I have tried to change the file gnome-terminal using the GUI but I do not have rights to save.

Please help.