Run this:
lxc launch ubuntu:22.04 mycontainer
In case you see this error message
Error: Failed container creation: No storage pool found. Please create a new storage pool
see How to fix lxd ‘Failed container creation: No storage pool found. Please create a new storage pool.’
Now you can connect to your container using
lxc exec mycontainer /bin/bash
If you want to prevent your docker container creating files as root, use
--user $(id -u):$(id -g)
as an argument to docker run. Example:
docker run --user $(id -u):$(id -g) -it -v $(pwd):/app myimage
Run
id -g
to get the GID of the current user’s primary group. Example:
$ id -g 1000
You can also get the GID of another user’s primary group:
$ id -g root 0
Run
id -u
to get the current user’s UID. Example:
$ id -u 1000
You can also get another user’s UID:
$ id -u root 0
Copy and paste this shell function into your bash or zsh:
function gzToXz { zcat "$1" | xz -c - -ev9 > "${1%.*}.xz" ; }This will decompress the file using zcat and pipe it into xz with the highest compression setting (-ev9). If you prefer less compression but more speed, use e.g. -5 instead of -ev9.
Use like this:
gzToXz my.gz
which will recompress my.gz to my.xz.
In case you want to recompress every .gz file in the current directory, use:
for i in *.gz ; do echo "$i" ; gzToXz "$i" ; done
It might be best to make a backup of the data even though I have used this script many times for my own data.
If you see an error message like this in Wireshark:
this is because your current user doesn’t have permission to capture packets from your network card.
This can be the case even if you have selected to allow normal users to capture packets during the Wireshark installation process. This is because the setting only takes effect after logging out and logging back in (or rebooting).
To fix the issue temporarily without logging out, run Wireshark as root: sudo wireshark
In order to fix the issue permanently, ensure your user is added to the wireshark group:
sudo usermod -a -G wireshark $USER
and then log out and log back in again (or reboot your computer).
You want to compile your LaTeX file on Ubuntu using latex or pdflatex but you see an error message like this:
! LaTeX Error: File `environ.sty' not found. Type X to quit or <RETURN> to proceed, or enter new name. (Default extension: sty)
sudo apt -y install texlive-latex-extra
This will install, among many other LaTeX files, environ.sty.
You want to compile your LaTeX file on Ubuntu using latex or pdflatex but you see an error message like this:
! Package babel Error: Unknown option `ngerman'. Either you misspelled it (babel) or the language definition file ngerman.ldf was not foun d. See the babel package documentation for explanation. Type H <return> for immediate help
sudo apt -y install texlive-lang-german
This will install, among many other LaTeX files, the files for the ngerman language.
You want to compile your LaTeX file on Ubuntu using latex or pdflatex but you see an error message like this:
kpathsea: Running mktexmf ecrm1200
! I can't find file `ecrm1200'.
<*> ...ljfour; mag:=1; nonstopmode; input ecrm1200
Please type another input file name
! Emergency stop.
<*> ...ljfour; mag:=1; nonstopmode; input ecrm1200
Transcript written on mfput.log.
grep: ecrm1200.log: No such file or directory
mktextfm: `mf-nowin -progname=mf \mode:=ljfour; mag:=1; nonstopmode; input ecrm1200' failed to make ecrm1200.tfm.
kpathsea: Appending font creation commands to missfont.log.
! Font T1/cmr/m/n/12=ecrm1200 at 12.0pt not loadable: Metric (TFM) file not fou
nd.
<to be read again>
relax
l.105 \fontencoding\encodingdefault\selectfont
sudo apt -y install texlive-fonts-recommended
This will install, among many other LaTeX files, ecrm1200.mf and ecrm1200.tfm.
.
You want to compile your LaTeX file on Ubuntu using latex or pdflatex but you see an error message like this:
! LaTeX Error: File `scrartcl.cls' not found. Type X to quit or <RETURN> to proceed, or enter new name. (Default extension: cls)
sudo apt -y install texlive-latex-recommended
This will install, among many other LaTeX files, scrartcl.cls.
On the command line, run
sudo mokutil --sb-state
This will tell you
SecureBoot enabled_
if secure boot is currently active on your machine or
SecureBoot disabled
else.
In case you see an error message like
bash: command not found: mkoutil
you need to install mokutil first using
sudo apt install mokutil_
Newer version 16 available: How to install NodeJS 16.x LTS on Ubuntu in 1 minute
Run these shell commands on your Ubuntu computer to install NodeJS 14.x:
curl -sL https://deb.nodesource.com/setup_14.x | sudo -E bash - sudo apt-get install -y nodejs
Instead of setup_14.x you can also choose other versions like setup_12.x. However, using this method, you can’t install multiple versions of NodeJS in parallel.
To install ddrescue, run
sudo apt -y install gddrescue
lsusb lists all the USB devices to your computer.
Example output:
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 003: ID 8087:0a2b Intel Corp. Bus 001 Device 002: ID 04f2:b5e8 Chicony Electronics Co., Ltd Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Each line represents a single USB device – but an USB device might also be internal to the computer and not connected to a physical USB port. For example, Bus 001 Device 003: ID 8087:0a2b Intel Corp. is an internal Bluetooth modem in my notebook.
Explanation:
Bus 001: The device is connected to the first USB bus (001) on the systemDevice 003: In the aforementioned bus, the device has been assigned the ID 003.ID 8087:0a2b: This is the ID assigned to that device. The first part (8087) is the Vendor ID (VID). The second part (0a2b) is the Product ID (PID). These IDs are assigned by the USB Implementer’s forum. This ID will always stay the same for any given device. If you buy a USB product multiple times, all of them will have the same ID.Intel Corp.: This is the description of the device. Often Linux can show you more information, but in this case it’s just the name of the manufacturer.A PPA (Personal Package Archive) is a repository where you can download packages, that is software, for Debian-based Linux distributions like Ubuntu.
In contrast to “normal” package source that are provided and maintained by distribution providers, PPAs can be created by anyone in order to publish one’s software or special versions of third-party software.
PPAs are hosted on Launchpad, a platform made and supported by Canonical, the company behind Ubuntu.
While in principle one could publish dangerous software on a PPA, in practice there is virtually no risk since:
Still it is good practice to keep in mind that installing software from anywhere – including PPAs – has a chance (although a very little one) to compromise your computer.
You are trying to run iotop but you see an error message like
Netlink error: Operation not permitted (1) The Linux kernel interfaces that iotop relies on now require root priviliges or the NET_ADMIN capability. This change occured because a security issue (CVE-2011-2494) was found that allows leakage of sensitive data across user boundaries. If you require the ability to run iotop as a non-root user, please configure sudo to allow you to run iotop as root. Please do not file bugs on iotop about this.
You need to run iotop as root:
sudo iotop
The reason for this is that iotop needs to access kernel interfaces that are only accessible to root users or if the user/process has the CAP_NET_ADMIN capability. In theory you could add this capability using sudo setcap cap_net_admin+ep /usr/sbin/iotop but on Ubuntu 18.04 this did not work for me.
You want to create a live USB stick e.g. gparted, Ubuntu etc and you quickly want to test it without rebooting your computer.
You can use qemu, a system emulator, to do that.
First, install qemu. On Ubuntu:
sudo apt -y install qemu-system-x86
Now find out what the block your USB stick is called (e.g. /dev/sdb). You can use lsblk to do this:
sudo lsblk
this will output, for example
[...] sda 8:0 0 447,1G 0 disk ├─sda1 8:1 0 549M 0 part ├─sda2 8:2 0 121,2G 0 part ├─sda3 8:3 0 1K 0 part └─sda5 8:5 0 325,4G 0 part / sdb 8:16 1 29,3G 0 disk └─sdb1 8:17 1 268M 0 part
/dev/sda is usually your own hard drive (in my case, a 500 GB drive – 447.1G listed). In my case, I use a 32 GByte USB stick for the live USB, which is /dev/sdb (29.3 GB).
Note: You want to use the drive block device (e.g. /dev/sdb), not the partition block device (e.g. /dev/sdb1)
Now you can run qemu like this:
sudo qemu-system-x86_64 -hda /dev/sdb -m 1024
Remember to replace /dev/sdb by your USB stick block device (which we identified before using lsblk).
-m 1024 tells qemu to use 1024 Megabytes = 1 Gigabyte of RAM. You might need to increase this depending on what you are trying to boot.
Note that this approach will try to boot using BIOS and won’t try to boot UEFI-only drives like the ones created by tuxboot. In order to use UEFI with qemu you first need to install OVMF (which is a UEFI emulator that can be used for qemu):
sudo apt -y install ovmf
then run qemu like this:
sudo qemu-system-x86_64 -bios /usr/share/ovmf/OVMF.fd -hda /dev/sdb -m 1024
Remember to replace /dev/sdb by your USB stick block device (which we identified before using lsblk).
Since qemu is an emulator, it will be slower than booting your computer from the stick – but you can keep your computer running while you are testing your live USB stick.
According to the manual, you can install tuxboot using
sudo apt-add-repository -y ppa:thomas.tsai/ubuntu-tuxboot && sudo apt-get update && sudo apt-get install -y tuxboot
Now you can run tuxboot using
sudo tuxboot
You want to capture a video using raspivid, e.g. using a command like
raspivid -o vid.h264
but you only see this error message:
* failed to open vchiq instance
with no video being captured.
Run raspivid using sudo:
sudo raspivid -o vid.h264
Now either the video will be captured or you will see another error message if there is another issue with your camera setup.
Add your user to the video group so you don’t have to run raspivid as root:
sudo usermod -a -G video $USER
You only need to do this once. After that, log out and log back in (or close your SSH session and connect again). If in doubt, restart the Raspberry Pi. See What does ’sudo usermod -a -G group $USER‘ do on Linux? for more details.
Now you will be able to capture video as normal user:
raspivid -o vid.h264