sed -l option for line-wrapping is not working

In short... yes you have misunderstood line-wrapping slightly ;)

-l N, --line-length=N
       specify the desired line-wrap length for the `l' command

So, it only works with the l command:

l      List out the current line in a ``visually unambiguous'' form.
l width
       List out the current line in a ``visually unambiguous'' form,
       breaking it at width characters.  This is a GNU extension.

If you want the output three characters per line, you could use this:

sed -nl 4 's/word1/word2/;l' output > output2

or this in GNU sed:

sed -n 's/word1/word2/;l 4' output > output2

Note that a trailing backslash (to escape the line break) is appended if there is not actually a new line (end-of-line is indicated by $ characters). We need to use the -n flag, because the l command is for viewing rather than editing, like the = command, and the line will appear as normal after l has output it in the requested form, unless suppressed by -n.

You might get more like what you actually want by simply breaking the file after every three characters:

sed 's/word1/word2/; s/.../&\n/g' output > output2

or to split after, say, 10 characters:

sed -r 's/word1/word2/; s/.{10}/&\n/g' output > output2


How do I change the amount by which the brightness increases or decreases?

Using xbacklight you can increase or decrease your brightness by whatever percent you prefer.

xbacklight -set 1

or xbacklight -set 0.5
it accepts integer of even fractions.


How to install previous Firefox version?

You may have two choice to choose for installing method:

Via Mozilla's ftp site (kudos for @Bhikku for sharing the link !). For example we're going to install firefox 50. First, remove any existing version.

sudo apt-get purge firefox

Then run following command to download firefox 50 source code, which comes as .tar file.

wget http://ftp.mozilla.org/pub/firefox/releases/50.0/linux-$(uname -m)/en-US/firefox-50.0.tar.bz2

Extract the package.

tar -xjf firefox-50.0.tar.bz2

Move firefox to /opt directory.

sudo mv firefox /opt/

Create symlink in order to set the new firefox as default.

sudo mv /usr/bin/firefox /usr/bin/firefox_old
sudo ln -s /opt/firefox/firefox /usr/bin/firefox

Via UbuntuZilla which offer .deb files, to install follow the instruction below.

Remove firefox first :

sudo apt-get purge firefox

Run following command to download firefox :

32 Bit

wget http://downloads.sourceforge.net/project/ubuntuzilla/mozilla/apt/pool/main/f/firefox-mozilla-build/firefox-mozilla-build_39.0.3-0ubuntu1_i386.deb

64 Bit

wget sourceforge.net/projects/ubuntuzilla/files/mozilla/apt/pool/main/f/firefox-mozilla-build/firefox-mozilla-build_39.0.3-0ubuntu1_amd64.deb

Install it :

32 Bit

cd Downloads/ && sudo dpkg -i firefox-mozilla-build_39.0.3-0ubuntu1_i386.deb

64 Bit

cd Downloads/ && sudo dpkg -i firefox-mozilla-build_39.0.3-0ubuntu1_amd64.deb

And firefox should run the 39 version

Quote from ubuntuzilla official wiki page :

  This is the home of the Ubuntuzilla project, hosts an APT repository with .deb repacks of the latest official release versions of Mozilla Firefox, Mozilla SeaMonkey, and Mozilla Thunderbird.


If you are using Debian Jessie (or Ubuntu 13.10+), try

sudo apt-get install lib32stdc++6


Installation php5.6 on Ubuntu 19.10 doesn't work even with ppa:ondrej/php

Finally, after 10+ hours i found out that my version of ubuntu doesn't work with Software Center properly, and for some reason couldn't use any ppa, not only ppa:ondrej/php. After installing Ubuntu 18.04.3 LTS (Bionic Beaver) everything starts working without any additional commands.

So my advice for those who struggle with simillar problem, before installing ppa, learn what ppa is, then:

sudo apt-get upgrade
sudo apt-cache search php | wc -l #in my case it was php, you could ask for any other package, this command will show how much packages available till now
sudo add-apt-repository ppa:ondrej/php #it could be any oher repository
sudo apt-get update
sudo apt-cache search php | wc -l #if number is the same as after second step, it means that you probably have the same problems as i had.

Sorry for poor english, try to do my best.


Settings and network missing, cannot connect to the internet

I had issues with this and I went into the grub menu and selected a previous image to get this working


Upgraded to 11.04, now its not loading the normal way

Ok,
  this sort of problem will need some more information, especially the hardware you are using and if you are using any non-standard drivers (either self installed, or via the additional hardware drivers window).

So - if you are happy to try a few things and report back by editing your question, I will likewise (if I have any further ideas), reedit my answer - obviously many of these "try this" stuff will need you to boot into your working kernel or via recovery mode.

1) Possible graphics issue?  Maybe you have installed a graphics driver?

Possible solution - remove or rename your xorg.conf file

sudo mv /etc/X11/xorg.conf /etc/X11/xorg.conf.backup

2) Possible new KMS issue with your graphics card

Try booting with nomodeset as your grub option as described in this AU question and answer

3) Possible new incompatible hardware issue preventing boot

Try removing all plugged in hardware except your monitor, keyboard and mouse.  Try to ensure you use a wired keyboard and wired mouse.

4) Possible the upgrade was not completed

Try running

sudo apt-get update && sudo apt-get upgrade

Any errors reported

5) Can you confirm how you upgraded your laptop - did you use update manager from v10.10 to 11.04 or via the live/alternate CD or some other mechanism?

6) Some strange power-management or interrupt issue?

Try booting with either acpi=off or noapic

7) Some sort of strange networking issue?

Try plugging in via a fixed wired connection and hardware disable any wireless card e.g. via BIOS or possibly some switch on the side of your laptop.

Please add to your question details of your hardware i.e.

lsusb
lspci
sudo lshw

N.B. also add to your question that this isnt an external screen issue as per your comment - so that that sort of information doesnt get lost with any other comments.  TIA


You can use Boot-Repair or manually update MBR with Windows type boot loaders syslinux or lilo from Ubuntu live CD or flash drive, or many Linux repair ISO.

Grub stage 1 & stage 2 refer to grub legacy which few now remember. Almost all instructions are for grub2. Ubuntu standardized on grub2 with 9.10 or five years ago.
Grub4dos is a version of grub legacy for use in NTFS partitions. But grub2 will also work in FAT32, NTFS or Linux formatted partitions.

Both grub legacy & grub2 use this to update grub menu. From Working install:

sudo update-grub

Boot-Repair will not work on grub legacy, but may offer to update to grub2 if your install is still currently supported.

https://help.ubuntu.com/community/Boot-Repair


How to install Python 2.5.4 in Ubuntu 11.10?

open your terminal and do these steps one by one.

wget http://www.python.org/ftp/python/2.5.4/Python-2.5.4.tar.bz2
tar -zxvf Python-2.5.4.tgz
 cd Python-2.5.4
./configure
make
sudo make install

that will install Python 2.5.4 in your Ubuntu.

hope that helps.


Graphics tablet (Huion WH1409) loads driver properly but no input is received on Ubuntu 20.04

I was able to get it working by disconnecting the usb cable and using the wireless adapter instead. This is a known bug, see: https://github.com/DIGImend/digimend-kernel-drivers/issues/317


Disable PCI network device and use USB Ubuntu 20.04

I suggest that you blacklist the driver for the internal device. From the terminal:
sudo -i
modprobe -r iwlwifi
echo "blacklist iwlwifi"  >>  /etc/modprobe.d/blacklist.conf
exit

You should be all set.


Make a one or two line bash script designed to be run as root which runs the command you want as as the other user, using su or sudo.

Add a check to the script to confirm that's only run as root to avoid strange error messages.

To run the command as another user, just sudo my-cli-tool ....

This is fast to create and memorable to use.


Remove Scopes in Ubuntu for Mobile Devices

Okay, so it appears you can remove/un-install most Scopes by searching for them in the Ubuntu Store (as opposed to removing them directly from the Dash)...

I say "most", because unless I am mistaken, some Scopes seem to be "locked" and unable to be removed/un-installed (such as The Weather Channel Scope).


How to convert an audio stream's format?

It should be something like this:

$ ffmpeg -i input-file.wav -acodec pcm_f32le -ar 96000 output-file.wav

And you have plenty plenty of choices if you use PCM, other codecs may be constrained to certain profiles.

$ ffmpeg -formats 2>/dev/null | grep endian
 DE f32be           PCM 32 bit floating-point big-endian format
 DE f32le           PCM 32 bit floating-point little-endian format
 DE f64be           PCM 64 bit floating-point big-endian format
 DE f64le           PCM 64 bit floating-point little-endian format
 DE s16be           PCM signed 16 bit big-endian format
 DE s16le           PCM signed 16 bit little-endian format
 DE s24be           PCM signed 24 bit big-endian format
 DE s24le           PCM signed 24 bit little-endian format
 DE s32be           PCM signed 32 bit big-endian format
 DE s32le           PCM signed 32 bit little-endian format
 DE u16be           PCM unsigned 16 bit big-endian format
 DE u16le           PCM unsigned 16 bit little-endian format
 DE u24be           PCM unsigned 24 bit big-endian format
 DE u24le           PCM unsigned 24 bit little-endian format
 DE u32be           PCM unsigned 32 bit big-endian format
 DE u32le           PCM unsigned 32 bit little-endian format

$ ffmpeg -codecs 2>/dev/null | grep endian
 D A D  pcm_bluray      PCM signed 16|20|24-bit big-endian for Blu-ray media
 D A D  pcm_dvd         PCM signed 20|24-bit big-endian
 D A D  pcm_f32be       PCM 32-bit floating point big-endian
 D A D  pcm_f32le       PCM 32-bit floating point little-endian
 D A D  pcm_f64be       PCM 64-bit floating point big-endian
 D A D  pcm_f64le       PCM 64-bit floating point little-endian
 D A D  pcm_lxf         PCM signed 20-bit little-endian planar
 D A D  pcm_s16be       PCM signed 16-bit big-endian
 D A D  pcm_s16le       PCM signed 16-bit little-endian
 D A D  pcm_s16le_planar PCM 16-bit little-endian planar
 D A D  pcm_s24be       PCM signed 24-bit big-endian
 D A D  pcm_s24le       PCM signed 24-bit little-endian
 D A D  pcm_s32be       PCM signed 32-bit big-endian
 D A D  pcm_s32le       PCM signed 32-bit little-endian
 D A D  pcm_u16be       PCM unsigned 16-bit big-endian
 D A D  pcm_u16le       PCM unsigned 16-bit little-endian
 D A D  pcm_u24be       PCM unsigned 24-bit big-endian
 D A D  pcm_u24le       PCM unsigned 24-bit little-endian
 D A D  pcm_u32be       PCM unsigned 32-bit big-endian
 D A D  pcm_u32le       PCM unsigned 32-bit little-endian


Can't install Guitar Pro 6 on 64-bit Ubuntu on laptop, but I could on desktop

You just need to install the libglu1-mesa:i386 package. You cannot downgrade the GL library only as used by the system to 32-bit, but you can have both 32-bit and 64-bit versions installed on a 64-bit Ubuntu PC.


Using F-Spot, how can I find the file location for a specific photo?

You could interrogate the f-spot database itself to search for the filename in question.  Once found, the file-location that f-spot was expecting will be available.  This method would be particularly useful if you've got lots of pictures to search for.

Install sqlite3:

sudo apt-get install sqlite3

Now dump the f-spot database:

sqlite3 ~/.config/f-spot/photos.db .dump > ~/filelocations.csv

Using LibreOffice Calc - open the file filelocations.csv and search using the filename with the missing picture.  The filename should exist in two rows - one or both of which should display your missing file location.

for example


How to install software using preseed.cfg Ubuntu 18.04.4?

Remove unnecessary lines
Ubiquity ignores preseed/late_command so there is no point in using it.
Hence you included the openssh-sftp-server package in this line:
d-i pkgsel/include string openssh-sftp-server vim cryptsetup build-essential libssl-dev libreadline-dev zlib1g-dev linux-source dkms nfs-common

So these lines can be removed:
d-i preseed/late_command string apt-install openssh-sftp-server;

# Success Installation - Tasks
ubiquity ubiquity/success_command string  \
    in-target apt install openssh-sftp-server;

How to use ubiquity
I tested your preseed file by using Ubuntu minimal iso which can be found here. On selection screen I moved the cursor to command-line install and pressed tab key. Notice the attributes which appeared in the bottom of the screen:
Ubuntu Installer
Then append these attributes, feel free to change the values:
locale=en_US hostname=ubuntu keyboard-configuration/modelcode=SKIP ubiquity url=http://192.168.0.1:8000/preseed-ubuntu.cfg

The preseed file can be hosted on localhost of your host machine, for example by using python3 -m http.server. Your IP address will differ obviously. Press enter and the installation will proceed and the instalator will only prompt you for repo server as it is not defined in your preseed file.
After installation is complete you can login and confirm that openssh-sftp-server and other packages are installed.


Sound not working after installing Ubuntu

Try this: Click the speaker icon in the top right of the desktop screen. Click sound settings. Under output, make sure it is set on the device that you want to play sound through. (I also had this problem when switching from Windows 10)


Stuck at 640x480 after rebooting on Ubuntu 20.0.4.1 LTS

I just experienced the same problem after upgrading to 5.8.0-36-generic this morning.
I installed the NVIDIA driver manually using the terminal some 5 months ago.
The quickest solution is so go to 'Software & Updates', click on 'Additional Drivers' and install the desired driver there.
(Can't say if this works for everybody)


The canonical way to resolve symbolic links is to use readlink.

To resolve the symbolic link /usr/bin/firefox:

readlink /usr/bin/firefox

Canonicalizing by following all symbolic links in between:

readlink -f /usr/bin/firefox

For example:

$ readlink /usr/bin/firefox
../lib/firefox/firefox.sh

$ readlink -f /usr/bin/firefox
/usr/lib/firefox/firefox.sh

Note that, for any file that is not a symbolic link, will resolve to itself:

$ readlink -f /bin/cat
/bin/cat


Is it possible to make my system not suspend when playing music and video?

Install xmacro (sudo apt-get install xmacro)
Create a file called "myxmacro" and give it the following content:

Code:

MotionNotify 90 90
MotionNotify 120 120

3. Create a file "no.idle.sh" and make it executable:

Code:

touch no.idle.sh
chmod +x no.idle.sh

4.4. Create a file "no.idle.sh" and make it executable:
Code:

touch no.idle.sh
chmod +x no.idle.sh

Give it the following content:

Code

    #!/bin/bash
# No.idle.sh prevents GNOME to turn IDLE
# if there is any sound sent to speakers
# This script requires the package "xmacro"
# (apt-get install xmacro)
###########################################
# This script requires a textfile called "myxmacro"
# with the following (dummy) content:
# ------------ myxmacro ------------
# MotionNotify 90 90
# MotionNotify 120 120
# ----------------------------------
# You need to fix the path to "myxmacro" in line 31
#
#############################################

# set Log-File
LOG=/home/YOUR_USERNAME/noidle.log
sound=0
silence=0

while true; do
    sleep 1
    Datum=`date +%d.%m.%Y-%H:%M:%S`

    # check if sound is sent to speaker
    if pactl list | grep RUNNING > /dev/null; then
        echo "[$Datum] Sound (Ping: $sound)" >> $LOG
        sound=$((sound+1));
        xmacroplay :0 </path/to/myxmacro
        silence=0
    else
        echo "[$Datum] Silence (Ping: $silence)"    >> $LOG
        silence=$((silence+1));
        sound=0
    fi
    #----------------------------------------------------
done

You need to:
- fix the path to the logfile in line 18

fix the path to "myxmacro" in line 31

Add the script "no.idle.sh" to your GNOME-Startup-Items, so that no.idle.sh is running on every startup.

Done.

What the script does:
The script checks every second, if there is any sound sent to the speakers (using the terminal command pactl list | grep RUNNING).

If music is running, it simulates mouse-movement (using xmacroplay). This has the effect, that your GNOME-session won't run IDLE (and as a result your PC won't suspend).

If there is no music played, it does nothing (so your session IS ABLE to run IDLE and after that suspends)

You can watch the script checking for music by typing in a terminal:

tail -f /path/to/noidle.log


Ubuntu 18.04 File manager app hard to read columns

they can be changed to black color.

but the simply way is to try some GTK+ themes from gnome-look.org website or from the default themes that comes out of the box in Ubuntu 18.04.

I have changed the color to black with the default theme "Radiance" that came up with Ubuntu 18.04 in the below way.

in order to change it. First you need to know which GTK+ theme is being used. to know that open Gnome-Tweaks application. if not yet installed, install it by the below command sudo apt update && sudo apt install gnome-tweak-tool or simply search in Ubuntu Software as "gnome tweaks".

Open Gnome Tweaks, look for the name of theme under Appearane-Themes-Applications

in my case i selected "Radiance" as my GTK+ theme, so when i open file manager, it looks like this.

now open the folder sudo nautilus /usr/share/themes/
look for the folder "Radiance" Open it and find the file nautilus.css in sub folder of "gtk-3.20" under "apps" folder.

Open the file nautilus.css and find the section at the top of the page

nautilus-desktop-window.background:backdrop,
.nautilus-desktop-window.background:backdrop {
    box-shadow: none;
}

.nautilus-canvas-item {
    border-radius: 5px;
}

.nautilus-canvas-item.dim-label,
.nautilus-list-dim-label {
    color: mix (@theme_fg_color, @theme_bg_color, 0.50);
}

.nautilus-canvas-item.dim-label:selected,
.nautilus-list-dim-label:selected {
    color: mix (@theme_selected_fg_color, @theme_selected_bg_color, 0.20);

and change it like

nautilus-desktop-window.background:backdrop,
.nautilus-desktop-window.background:backdrop {
    box-shadow: none;
}

.nautilus-canvas-item {
    border-radius: 5px;
}

.nautilus-canvas-item.dim-label,
.nautilus-list-dim-label {
    color: #000000; #here you can put any color you want
}

.nautilus-canvas-item.dim-label:selected,
.nautilus-list-dim-label:selected {
    color: #000000; #here you can put any color you want

Save the file and Close.
Logout or Reboot to see the change.


Xorg Applications not working on Wayland after update to Ubuntu 20.10

I'm having the same issue from 20.04 -> 20.10 with snaps like VLC & Spotify.
I did some research and found this: https://forum.snapcraft.io/t/apps-wont-run-and-crash-on-gnome-wayland/20322/7
Apparently it's a new "bug". Only workaround is to use X11 for now.


To add read and write permissions to the Other group, assuming that you are the Owner and/or belong to the Group group and that the partition's mount point is /media/<username>/<partition_mount_point>:

chmod o+rw /media/<username>/<partition_mount_point>

If you are not the Owner and you don't belong to the Group group, you'll need to use sudo:

sudo chmod o+rw /media/<username>/<partition_mount_point>

To add read and write permissions to yourself, assuming that you belong to the Group group:

chmod g+rw /media/<username>/<partition_mount_point>


Is there any way to get CVE or USN ids that need to be installed?

This can be solved in two steps:

Find security related packages that need to be updated: I am running a modified version of the update-notifier's apt-check script which takes an additional switch: --security-package-names, and outputs only the security related package names
Look up CVE's against those packages: The ubuntu-cve-tracker project on launch pad can be used

Here are the step by step instructions:

Getting a list of security related packages

I have it as a gist (until I create a merge request in the relevant project in launchpad). For now it can be run as follows:

curl -s https://gist.githubusercontent.com/ahmadnazir/c2444d6b09fd7bb4963a13bc577d92a3/raw/0231b94a4e46abe0a5959de5f84feda76ad2eb9d/apt-check.py \
  | python /dev/stdin --security-package-names \
  | column -t -s , \
  | sort

This gives an output of the format: package name, installed version, and candidate version:

...
thunderbird                          1:38.6.0+build1-0ubuntu0.14.04.1     1:38.8.0+build1-0ubuntu0.14.04.1
thunderbird-gnome-support            1:38.6.0+build1-0ubuntu0.14.04.1     1:38.8.0+build1-0ubuntu0.14.04.1
thunderbird-locale-en                1:38.6.0+build1-0ubuntu0.14.04.1     1:38.8.0+build1-0ubuntu0.14.04.1
thunderbird-locale-en-us             1:38.6.0+build1-0ubuntu0.14.04.1     1:38.8.0+build1-0ubuntu0.14.04.1
tzdata                               2016b-0ubuntu0.14.04                 2016f-0ubuntu0.14.04
tzdata-java                          2016b-0ubuntu0.14.04                 2016f-0ubuntu0.14.04
vlc-data                             2.1.6-0ubuntu14.04.1                 2.1.6-0ubuntu14.04.2
vlc-nox                              2.1.6-0ubuntu14.04.1                 2.1.6-0ubuntu14.04.2
wget                                 1.15-1ubuntu1.14.04.1                1.15-1ubuntu1.14.04.2
...

Looking up CVE's for the packages

Check out ubuntu's cve tracker project on launchpad:

bzr branch lp:ubuntu-cve-tracker

Let's say you want to get the CVE for the wget package, you can run the following script

cd ubuntu-cve-tracker
./scripts/pkg_status wget

This gives an output similar to following:

                                           precise         trusty      vivid/spo       vivid/uc           wily         xenial        yakkety
CVE-2016-4971 wget:                       released      released*        needed*            DNE       released       released       released [out of sync] SUPPORTED medium

The first column in the result shows the CVE.

Note:

Make sure that /etc/apt/sources.list has the relevant sources for the scripts to work. I modified the some of the scripts to work only with trusty which is why I didn't have to do this.


How do I adjust the terminal shell window width?

If you are referring to gnome-terminal, you can go to the menu item Edit->Profile Preferences, check "Use custom default terminal size" and put in the character dimensions you prefer.


My system setting wiped out after I uninstalled my lampp

Try to run:
$ unity-control-center.

If doesn't appear try to install:
$ sudo apt-get install unity-control-center


While writing npm install learnyounode -g on terminal? 12.04 LTS

This is an issue related to SSL certificates, and it's most common when you're trying to run npm from behind a proxy.  There are a few ways to remedy this issue:

You can reset npm's proxy settings by running:

npm config rm proxy
npm config rm https-proxy

You can use the non-https version of npm:

npm config set registry http://registry.npmjs.org/


Cintiq 27qhd stopped working, now only registers first touch

I don't have that tablet, but the new release of the wacom drivers --- see the mailing list announce --- are specifically commenting things about Cintiq devices. Maybe is worth trying to compile the latest driver.

You can use my old answer for 0.20 as a base, although I think the compilation method has changed a bit; see also my answer here and the comments for help.

Good luck!


Is there a snip tool (Windows) equivalent for ubuntu?

Don't know exactly what you mean, because I don't use any windows snipping tool.
I use "Screenshot 3.36.0" (install package gnome-screenshot). Which I have bound to the "print-screen"-button.
Which this you can copy the screen (or window) to the clipboard or save to file.


Perhaps systemctl disable bluetooth.service will work?  Do you actually have a bluetooth device?


did You try this:

   apt-add-repository ppa:relan/exfat
   apt-get install fuse-exfat

?

more: http://apcmag.com/how-to-enable-exfat-in-ubuntu.htm


Considering getting IR remote, will it work with things like VLC?

There is a program called LIRC which is used for IR stuff in Linux. You mostly can't expect it to work out of the box. You may have to bind the buttons with specific actions yourself. So you'll need to do some reverse engineering stuff.

It is medium to hard, depending on how standardised your remote codes are, which affects how easily lirc can detect them automatically for you. If that part gets over easily, then it should be smooth sailing.

It is a command line tool. To get started, go here https://help.ubuntu.com/community/LIRC

It has configuration files shared by others. So, if you find your remote already on the database, then you could simply grab that file. Otherwise, you'll have to play your buttons one by one, grab the codes with your IR Receiver (of course, with the help of LIRC) and make the config file for your remote.


SSH public key authentication doesn't work

Anything in log files, particularly /var/log/auth.log?  You might also double-check permissions on the .ssh directory and files.

I haven't had to modify sshd_config for this kind of access, myself.   I am wondering if your modification broke things, especially the AuthorizedKeysFile line.
Typically, you would want to put the authorized_keys under $USER/.ssh .

Here are the permission from a user on one of my servers:

:~/.ssh$ ls -ld .
drwx------ 2 rrd rrd 4096 May 28 17:57 .

:~/.ssh$ ll
total 280
-rw-r----- 1 rrd rrd   4351 May 22 16:20 authorized_keys
-rw------- 1 rrd rrd   1679 Apr 27  2012 id_rsa
-rw-r--r-- 1 rrd rrd    399 Apr 27  2012 id_rsa.pub
-rw-r--r-- 1 rrd rrd 266138 Jun 13 00:18 known_hosts

Make sure the individual files are at least this restricted.

As guntbert points out, also check that the directory and files are owned by you.  The permissions won't make sense (or work) otherwise.

Who owns the keys in authorized_keys on B? (The bit that says user@host after the key.) Is it root@A ?

That is, in looking at ~/.ssh/authorized_keys, what is the equivalent of bert@etherbert for your set-up:

ssh-rsa AAAA...ffsII8dSaDF33 bert@etherbet

I would just edit the remote .ssh/authorized keys manually for testing, putting in the id_rsa.pub contents of the user you are intiating the connection with.

Make sure you are coming from the user that has the key in the remote authorized_keys file.


DIgisol Wireless USB dongle is not working in UBUNTU 12.10

Digisol is not getting connected in my Ubuntu, even I after installed the scripts provided by the device, it is showing connection profile but is not getting connected.Some times it is showing Registered in Network but immediately disconnecting.Also, device is not getting detected immediately after attaching the device to the system


I can't open any virtual machine on VirtualBox

Please try these ways:

Go to your BIOS settings (By pressing F12, F2, F8, or Delete, ... depends on machine).
And make sure Virtualization option (It can be have names like VT-d or AMD-V or Intel Virtualization Technology or Virtualization or ...) to be enabled. (And if its be disable make it enable)

Go to VirtualBox settings >> System >> Motherboard
And then increase RAM size (For example to 2GB is good).

Go to VirtualBox settings >> System >> Acceleration
And then Uncheck the Enable VT-x/AMD-V option.


How do I set a fallback for a GTK+ theme?

Yes this is possible. I would suggest creating a hybrid theme. This way you won't need to edit files as root, or experience any complications when a theme you have modified is upgraded.

First create a copy of it under ~/.themes:

  mkdir -p ~/.themes

  cp -r /usr/share/themes/NOX ~/.themes/NOX-Custom

Next, copy over the gtk-3.0 subfolder from an existing theme. For example:

  cp -r /usr/share/themes/selene/gtk-3.0 ~/.themes/NOX-Custom/

Finally, customize name for your new theme in the index.theme file found under the theme folder.

  gedit ~/.themes/NOX-Custom/index.theme


Installation stuck at "Retrieving file 43 of 93"

If you have this problem installing inside of VMWare (I am using Fusion), then simply disconnect the network adapter in the VM.  That immediately allowed my installation to continue.

In Oracle VM VirtualBox:


I did not find what caused the slowdowns, but I did a manual downgrade to temporarily fix the problem.

I removed the program through Ubuntu Software, and installed it manually using a .deb of a earlier build, which was available on Discord's own website. The slowdowns are completely gone. I have reported the bug to Discord through their own channels.

EDIT: Discord has 0.0.8, which was a version before the slowdown troubles, on their site: https://discordapp.com/api/download?platform=linux&format=deb


You can install the extensions from the zip file by opening up the zip file and compiling and building the extension that you want to install.  You can build the extension by running from a terminal prompt:

$ ./build [extension name]

Replace extension name with the name of the extension you want to build.  For example you could build the nemo-terminal extension with:

$ ./build nemo-terminal

During the compiling and build process you may get errors indicating that you need certain development packages.  You can install a dependence package using apt-get.  For instance once of the packages used for some of the extensions is libglib2.0-dev.  If you don't have it installed you'd have to install it.

$ sudo apt-get install libglib2.0-dev

Most of the github downloads will have instructions of how to build the packages included in the zip or the git-hub directory branch.

There may be occasions where you might have to read some of the comments on the site to resolve some of the issues the users are having when compiling and building some of the individual packages.


nginx dependency problem trying to upgrade

The problem is that nginx-full depends on nginx-common, this means that you can't install  the package nginx-full without have a specific version of nginx-common.

Here is an question dedicated to this problem, but the resolution is very extensive, reaching to, not only one, but different cases. So I will show you a short but effective method.

Actually, I don't know how to install that version of nginx-common, but I know that you will solve your problem by reinstalling all the package. To do that you must enter the following command in a terminal.

sudo apt-get remove nginx* && sudo apt-get install nginx-full


https://www.libreoffice.org/bugzilla/show_bug.cgi?id=67993

ALTGR key should be used with vowel key (a i u e y o v r) to get "ಅ ಇ ಉ ಎ ಐ ಒ ಔ ಋ"

shift key + a to get ಆ

ALTGR + shift key should be used with vowel key (i u e o r) to get "ಈ ಊ ಏ ಓ"


Is there a way to get the real modified time of a file?

What touch can set is the “atime” or “mtime”.  POSIX systems also track the “ctime”, “inode change time”.  Several alternatives for getting it:

$ ls -lc _file_
$ stat -c %z _file_
$ perl -MDate::Format -e '@_ = stat $ARGV[0]; print ctime $_[10]' _file_

Any change to the file's data or metadata (hard link count, permissions, etc.) sets the “ctime”.


How Can I create a bootable USB for Ubuntu on Windows 10 from an iso image?

You can use YUMI, UNetbootin and other programs for this. The two named programs feature an easy-to-use and self-explanatory GUI. There you select your USB drive and the ISO image and everything else is taken care of by the program.


How do i factory reset my pc back to Factory settings on ubuntu 16.04 .1 LTS

If you didn't choose to install Ubuntu alongside Windows, then you're only option is to get a Windows media (a DVD or USB) and reinstall. There's no option for "factory reset" back to Windows once the Windows partition was completely removed.

If you go to the "Windows 10 ISO" download page from your Ubuntu computer (either Firefox or Chrome will do - and likely many other browsers, but it must be from Ubuntu, or else Microsoft will just redirect to to the EXE file), you'd be able to select and download an ISO image for Windows 10, after which you can use the Ubuntu DVD Creator to burn the ISO image to a blank DVD, assuming you have a DVD drive available.

If you don't have a DVD drive or blank discs to use, then you can write the downloaded ISO image to a USB drive - though that process is more complicated and requires to use a terminal to run some of the steps. Follow the process detailed in this Ask Ubuntu answer (please note that it is not the top voted answer - though you may need to read the top voted answer as well to help you copy the contents of the ISO image to the USB drive, as required).


Hp printer not printing correctly after ubuntu 20.04 install

Remove ippusbxd:  (run sudo apt remove ippusbxd in terminal)
Delete and reinstall the printer using the GUI printer utility
Print a test page

This worked for me after hours of troubleshooting, I hope it works for you as well!
You might also want to read these related questions where more knowledgeable people than me explain how all printers now are "network printers" or something like that. Apparently removing ippusbxd isn't the most elegant solution, but as long as it works I'm happy :-)

Getting HP DeskJet 3700 working with Xubuntu 20.04

Canon PIXMA MP230 doesn't work with Ubuntu 20.04


There is kdeglobals file in gtk-3 theme folder - under [WM] section there is setting activeForeground. That setting affects font color

In addition , I was previously successful using this method for the Malys Theme (it may be that some themes are compiled differently)

Go to /usr/share/themes/theme name/gtk-3.0 where there are are .css files
You can modify font colors in these files through gedit.

Make a back up copy of the .css file before you start (it case things
go wrong, you can then revert back)
Modify the gtk.css file in gedit.
Put in the hexadecimal code of the color you want  (This
might help)

**Only do this if you are comforatable editing CSS files.""


Access Windows 10 Shared Folder from Ubuntu 18.04

There was a change in both Windows 10 and Samba.  Some of the details are explained here.

The browse by just clicking isn't working, but you can get there by entering the shared folder link in the address field.  Use the server's IP address or the computer name for the share.  In the example I'm using the IP address of the Windows 10 server:

Use Keyboard shortcut Ctrl+L to type in pathname:

smb://192.168.1.102

Typing that in the file browser will bring up authorization prompt.  Use the credentials from your Windows 10 server. This will display all the available shares.  You can then click on the share you want access to.

There are two changes steps you may have to do.  Set client max protocol = NT1 for the downward compatibility in the /etc/samba/smb.conf file.  Place the entry just below the workgroup = WORKGROUP line.

It should look like this:

#======================= Global Settings =======================
[global]

client use spnego = no
client NTLMv2 auth = no

## Browsing/Identification ###
# Change this to the workgroup/NT-domain name your Samba server will part of
   workgroup = WORKGROUP
   client max protocol = NT1

Once you have manually accessed the desired share, you can make it easily accessible in the future by bookmarking it.  You can do this with the keyboard shortcut: Ctrl+D.

You can easily rename your bookmarks to something friend and meaningful by right-clicking the name that appears in the File Browser's sidebar.

Install necessary packages:

You may have to install smbclient, which will ensure you have the necessary dependents such as the cifs-utils and the actual /etc/samba/smb.conf file.

$ sudo apt install smbclient


Disable dash docking feature in gnome shell

Try these two extensions:

https://extensions.gnome.org/extension/307/dash-to-dock/

https://extensions.gnome.org/extension/17/dock/

I had tried the latter for some time and it worked ok.


Red light from headphone jack Macbook Pro running Ubuntu 14.04

I'm using ubuntu-16.04 and after so many attempts I figured out the solution.

These are the steps to solve red light audio jack issue in Macbook.

open system settings.
go to output tab, select speakers - Built-in Audio option
under Play sound through category.
look for the mode option under settings for speakers category.
Change mode from Analog Stereo Output to Analog Surround 2.1 Output or Analog Surround 4.1 Output.

Enjoy!


OpenGL not working after kernel update (12.04)

Yes, reinstalling drivers from .run file fix it (from repository it has some issues for Nvidia-210). Will I need reinstall driver eveytime after next kernel updates?


I'm not familiar with tcsh, so there might be a good fix for this in tcsh.

That said, I am familiar with bash, and can see what might be causing this problem. Note the quoting here:

set OPT="-r -c -nH -np -nd -e robots=off -P PATH/$ID -A 'pattern*.extension' -a $ID.log"

There's an outer layer of quotes and additionally, an inner layer of quotes for pattern*.expansion. Presumably you're using the inner layer because that's how it would look like you if you actually typed the command in the shell.

The way this works, the shell performs various expansions on the command line, like variable expansion, wildcard expansion, etc. So in a command like:

wget $OPT ...

the shell will expand $OPT to its contents, perform field splitting, separating out the contents of $OPT to separate words, and wildcard expansion (or globbing), which is where the command fails:

> set foo="'*'"
> echo $foo
echo: No match.
> echo "$foo"
'*'

Note how the quotes around $foo prevented the error? But you cannot use quotes in your script, since quotes will prevent field splitting as well, and you are relying on field splitting so that the various options in $OPT (-r, -c, etc.) are passed as separate arguments to wget.

Here's a demo of the differences with and without quoting:

> printf "|%s|\n" "$OPT"
|-r -c -nH -np -nd -e robots=off -P PATH/foo -A 'pattern*.extension' -a foo.log|
> printf "|%s|\n" $OPT
printf: No match.
> printf "|%s|\n" -r -c -nH -np -nd -e robots=off -P PATH/$ID -A 'pattern*.extension' -a $ID.log
|-r|
|-c|
|-nH|
|-np|
|-nd|
|-e|
|robots=off|
|-P|
|PATH/foo|
|-A|
|pattern*.extension|
|-a|
|foo.log|

I imagine this might work if you used:

set OPT="-r -c -nH -np -nd -e robots=off -P PATH/$ID -A pattern*.extension -a $ID.log"

But that risks wildcard expansion if you don't use "$OPT", and the working directory has files matching pattern*.extension:

> touch pattern-abc.extension
> printf "|%s|\n" $OPT
printf: No match.
> set set OPT="-r -c -nH -np -nd -e robots=off -P PATH/$ID -A pattern*.extension -a $ID.log"
> printf "|%s|\n" $OPT
|-r|
|-c|
|-nH|
|-np|
|-nd|
|-e|
|robots=off|
|-P|
|PATH/foo|
|-A|
|pattern-abc.extension|      <---- tcsh expanded pattern*.extension
|-a|
|foo.log|

Again, I am not skilled enough in tcsh to suggest a good solution, but I do know a decent solution in bash:

Use arrays to build command lines.

In bash, your script would look like:

#!/bin/bash
ID=$1  #just an ID for subfolders
shift

OPT2=("$@")  #additional options that can be passed to wget
OPT=(-r -c -nH -np -nd -e robots=off -P PATH/"$ID" -A 'pattern*.extension' -a "$ID".log)
OOP=(--progress=bar:force --no-check-certificate)

echo wget "${OPT[@]}" "${OOP[@]}" "${OPT2[@]}" "https://.../$ID/"
wget "${OPT[@]}" "${OOP[@]}" "${OPT2[@]}" "https://.../$ID/"

I have made a few changes here. You have assigned $3 to OPT2, but then loop over all arguments (in effect, that's what while ($1 != '') ... shift will do), but without using those arguments in the loop, which doesn't make sense - the second argument to the script is effectively ignored, but the third argument is used as an option. Given the Python snippet, I'm going to assume only the first argument is the ID and the rest are options to wget.

Now, using an array like so:

OPT=(-r -c -nH -np -nd -e robots=off -P PATH/"$ID" -A 'pattern*.extension' -a "$ID".log)

Allows us to expand to each separate word in the array, while not risking field splitting or filename generation, using "${OPT[@]}" in bash:

$ printf "|%s|\n" "${OPT[@]}"
|-r|
|-c|
|-nH|
|-np|
|-nd|
|-e|
|robots=off|
|-P|
|PATH/foo|
|-A|
|pattern*.extension|
|-a|
|foo.log|

Every argument perfectly preserved.


Clean Install of Ubuntu 14.04 on Dell Latitude e6420. New working HDD

Although you say you "configured the boot to be UEFI", please make sure that your PC has an
EFI based BIOS, because DELL Latitude e6420 is an older model, which may have legacy BIOS.

Boot from Ubuntu installation media, open GParted - View - Device Information.

In case it has Legacy BIOS, make sure that the disk has a msdos partition table.
In case it has an UEFI BIOS, make sure that the disk has a gpt partition table.

When it does not match, create a new matching partition table and reinstall.
More comprehensive information on how to prepare the disk you find here.


How to access the rest of a 500 GB hard drive that ubuntu is installed on?

It turns out the rest of the 450 GB is in the /temp directory, that was not shown in the left-hand source directories of the folders tab.

My hard disk has now been resized using gparted so that the Ubuntu partition has ~200 GB. This achieved by booting to a USB stick with Ubuntu 16.04 on it, as the hard drive could not be re-partitioned whilst I was using it.


If you open Nautilus (the icon in the launcher that looks like a small filing cabinet).
This where you will find all your files and folders.

To the left there should be a heading named devices, it should show up there.

I am displaying here my 80gig partition with windows install on it.


At some point ejabberd must have created a logrotate file to rotate its logs. The daily logrotate job, scheduled in /etc/cron.daily/logrotate, reads any job configuration files in /etc/logrotate.d and the /etc/logrotate.conf file, and actions the instructions in them. As there is no /var/log/ejabberd directory, the daily logrotate job reports outputs an error.

As mentioned in heemayl's answer any output from a cron job is sent in an email to the recipient in the MAILTO variable.

To permanently disable this behaviour, the logrotate job for ejabberd should be stopped. Look in /etc/logrotate.d for the ejabberd file, remove it with:

sudo rm /etc/logrotate.d/ejabberd


How do I find patches in debian packages?

This usually depends on the type of patch system which the package uses.

There are 3 types of patch systems for Debian packages:

Quilt (most widely used)
Cdbs + Simple Patchsys
dpatch

All patch systems store patches in debian/patches. You can use the what-patch command in package ubuntu-dev-tools  to find out which patch system a package is using.

Introduction of Quilt:

Quilt patches can be easily manipulated using the quilt command from a terminal. The quilt command is a part of package quilt .

This page will help you getting along with quilt. Also check out the quilt manpage by running

man quilt

in a terminal.

Now for cdbs + simple-patchsys:

These patches are manipulated commonly by a script called cdbs-edit-patch in package cdbs . You can edit patches like this:

cdbs-edit-patch *PATCHNAME*

You can add new patches like this:

cdbs-edit-patch *NEW_PATCHNAME* *PREV_PATCHNAME*

Where *PREV_PATCHNAME* is the name of the patch after which *NEW_PATCHNAME* will apply.

dpatch:

dpatch  patches can be manipulated using the script dpatch-edit-patch in package dpatch . The usage of dpatch-edit-patch is exactly the same as cdbs-edit-patch above.


You are correct in assuming that patches need to be applied to source code, not the compiled package that's installed on the system. This is because the .patch file contains information about differences in source code files. The compiled version of the program is in binary form and is unchangeable.

Keep in mind that apt has a handy tool for autobuilding packages from source, apt-source.


How to free space in root directory and delete unnecessary kernel files?

You can use Ubuntu Tweak to easily clean up your system. It's a graphical tool which let you tweak the system and also, into the "Janitor" section you can clean the system (clean browser cache, app cache, old kernels, etc) using a graphical tool, so you don't have to do this manually.
You can download & install it from http://ubuntu-tweak.com/

After that you removed the old kernels, in order to remove them form /boot and grub too, you have to update your grub config. To do this, just run:
sudo update-grub


error 127 found while installing gtk themes in ubuntu 18.04

I have solved this error by starting my laptop in recovery mode. Then I selected dpkg and installed broken packages. Then I restarted my laptop and the error was solved.


What Software to Use for Tagging/Annotating/Commenting/Highlighting Video Footage?

Best Solution: Totem

In Totem you can create custom chapters. By choosing “Chapters” from the “View”, you get a sidebar for working with chapters:

By clicking the “Add New Chapters” button in the sidebar and then using the buttons at the bottom of the sidebar, chapter markers can be added, deleted and saved:

Saving creates a new file with the same name as the video file (but with a different suffix) right next to the video file. The new file is in the XML-based Continuous Media Markup Language (CMML) format, i.e., it can be easily searched with for example grep.

Since the CMML format is open, such chapter files can also be created by other tools and loaded into Totem. This might become handy, for example, when extracting HiLight tags from GoPro cameras and converting them to CMML for viewing in Totem.

Honorable Mention: VLC

VLC has a “Custom Bookmarks” item in the “Playback” menu that can be used for marking positions in videos. These boomarks can be saved into a playlist from where they can also be loaded again.

Unfortunately the feature seems to have been partly broken for a while now.


Look at the lvm config backups in /etc/lvm/archive and if you can find the one with the correct settings ( should be the most recent ), then resture it with vgcfgrestore


System runs out of space, space returns after restart

This is not an answer, but some tips on how to identify the source of the problem.

To find what is taking the space, you can do the following:

First, get a listing of the occupied space of the root folders with sudo du -h -d 1 --exclude=/proc --exclude=/run /. This will give you some output like the following:

309M    /opt
3,8G    /var
512K    /root
(...)
3,5M    /lib32

Save this information somewhere and wait for the system to start filling again. Then, you execute the same command and compare the outputs. This should give you a hint on what is growing and taking your space.
Then you can use ncdu to investigate further. Supposing that the folder that grow more was /var, you can use sudo ncdu /var. This is a curses application, so you can use the arrows and enter to navigate between the folders and get to the root of the problem.

But as I said in the comments, the fact that the space is reclaimed after yo restarted your system points to /tmp. This folder is used to store temporary files and is cleared whenever you restart by default. As you guess, as a server would be rarely rebooted the files there will start to pile up...


Icons and nautilius windows looks strange

I had the same problem. This occurred after I installed the proprietary NVidia drivers.

For me I had to launch nvidia-settings from the command line and tweak a few resolution settings and save this to my x.config file. This is the only way that things become persisted between logins.

You might look at settings using xrandr before and after using your "nautilus -q" tip. I'm not really sure what the base issue is, but I and several of my friends have noticed problems with nautilus looking a little too "old school" with the latest nvidia drivers.


Problem when trying to run a compiled C++ file (uses OpenGL). Error: "Inconsistency detected by ld.so: dl-version.c: 224"

I got the very same problem with a much more simpler code :

#include <string>
#include <GL/gl.h>
#include <GL/glut.h>

static void displayFunc(void){
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glutSwapBuffers();
}

int main(int argc,char **argv){
    std::string nimportequoi;

    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_DEPTH);

    if(glutCreateWindow("") == 0) return 1;

    glutDisplayFunc(displayFunc);
    glutMainLoop();
    return 0;
}

The problem comes from the introduction of std::string (I suppose any C++ related standard lib objet will do the same) in conjunction with GL (i try a program without GL that works fine). If I comment this line, it works !


I've tried running Ubuntu 14.04 which I could at least get into live mode by using Legacy in the BIOS

If the computer already boots another OS in EFI/UEFI mode, as do the vast majority of computers that shipped with Windows 8 or later, then this is the wrong thing to do. I know a lot of Web sites say to do it, but THEY'RE WRONG! Setting this boot mode can work around some problems with booting the installation medium when that medium is prepared incorrectly, but the cost is even worse problems down the line. The result is either a repair or going back to square one to re-create the boot medium and re-install. It's better to do it right from the start by getting the installation medium to boot in EFI/UEFI mode. This can usually be done by using a different tool to prepare the boot medium (Rufus, Unetbootin, and dd can all usually do the job) or by adjusting options in the tool you used to create the boot medium. For more on this subject, see my page on the CSM.

The BGRT message you're seeing has been popping up a lot lately. See, for instance, this question and its answers. I have no personal experience with it, but my impression is that it's not a critical problem, and that the subsequent hang is unrelated.

If the computer is new and you can't get Ubuntu to boot on it, my recommendation is to return it for a refund and get something else. That said, there may be a solution; I'm not familiar with your particular computer or its quirks. You can find a list of laptop and desktop computers certified for use with Ubuntu here. Be aware, though, that many of these systems are sold pre-loaded with Ubuntu, and many of these include drivers or other software that's not a standard part of the distribution, so you may need to track those down if you buy a model that doesn't come with Ubuntu pre-installed.


There's no image for 14.04, to get the current (15.04) img run the following commands:

$ wget http://releases.ubuntu.com/vivid/ubuntu-15.04-snappy-armhf+bbb.img.xz
$ unxz ubuntu-15.04-snappy-armhf+bbb.img.xz


Why can't I change some file permissions?

Probably you do not have permission for change permissions.

By the way, in Linux any file with the execute permission is considered as executable. No matter if it actually contains anything that could be executed or not.

You can set Nautilus to always open files instead of executing them. To do that just open a file manager window, go to Edit->Preferences, and on the Behavior-tab set it to "View Executable files when they are opened"

Also try to change permissions in terminal using chmod -x (and if you have no permissions ro change permissions sudo chmod -x), something like sudo chmod -x file.tex (here r are saying that file.tex is not executable).


So I seem to have made an error (though I followed guides to the tee). Either I typed in the path wrong multiple times (and copypasted it wrong) or I made a formatting error... anyway.
The code that solved it was:

sudo chown -R $JONAS:$JONAS /media/jonas/483ad320-0a82-476a-813e-e49ed6034def

Before that, the -R was used at the end, but that doesn't explain that the media wasn't found. Oh well...


Using rename, keeping part of the search regex

You can either use capture groups:

$ rename -n 's/(\d)a/$1.1/' *
Area.v2a.2.h -> Area.v2.1.2.h
Base.v2a.c -> Base.v2.1.c
Slider.v4a.h -> Slider.v4.1.h

Or you can use a lookbehind:

$ rename -n 's/(?<=\d)a/.1/' *
Area.v2a.2.h -> Area.v2.1.2.h
Base.v2a.c -> Base.v2.1.c
Slider.v4a.h -> Slider.v4.1.h

Or, similar to a lookbehind, the 0-length assertion \K, which means "forget everything matched until this point":

$ rename -n 's/\d\Ka/.1/' *
Area.v2a.2.h -> Area.v2.1.2.h
Base.v2a.c -> Base.v2.1.c
Slider.v4a.h -> Slider.v4.1.h

Note that I used the shorter \d instead of [0-9]. The two are equivalent, but rename is a perl script, so understands the syntax of Perl Compatible Regular Expressions (PCRE).

Note that this will only change the first occurrence of a number followed by an a. This may or may not be what you need, depending on your file names.

The -n makes rename show what it would do without actually doing anything. once you've confirmed that it works as expected, remove it to actually change the file names.


The Ubuntu Wiki has some instructions for 10.04 on this. Also mdm is mentioned sometimes, and maybe you can follow this 10.10 tutorial.


Is Ubuntu developer's preview going to be installable on Nexus 10 (besides Nexus 7)?

The Touch Developer Preview of Ubuntu will be published on the 21st
  February 2013 with installation instructions for the Nexus 7 and Nexus
  10 tablet devices as well as smartphones such as the Nexus 4 and
  Galaxy Nexus. Installable images and source code will be available
  from developer.ubuntu.com.

http://www.ubuntu.com/static/u/files/section/devices/Ubuntu-tablet-press-release-en.pdf


Looking for a wallpaper with paper airplanes

Did you look at the list of 'standard' wallpaper presented to you when you select wallpaper? If it is standard, then it should be in the same place as all the other standard options.


How to log all the output displayed at screen?

script

The standard tool is the script command. Here a description from the manual, man script:

  DESCRIPTION
         script  makes  a  typescript  of  everything  displayed on your terminal.  It is useful for students who need a hardcopy
         record of an interactive session as proof of an assignment, as the typescript file can be printed out later with lpr(1).

If you need more professional tools you can search for one on this link.


I've had similar problems and I figured that in most cases the only thing you have to do is

sudo dpkg --configure -a

and then

sudo apt-get install -f

If that doesn't help, you should edit file /var/lib/dpkg/status and delete whole blocks of broken packages. Then repeat the first two commands and that's it.


Change /usr/lib to /usr/lib32 for eclipse to look for *.so files

You're trying to run 32-bit eclipse (supposedly downloaded from eclipse.org, because Ubuntu package manager wouldn't let you do that) on 64-bit Ubuntu. While theoretically it may be possible to make this work, the easiest would be either to install eclipse using Ubuntu Software Center, or, if you have reasons to do so, download the proper installer from from eclipse.org

Their website has separate downloads for 32-bit and 64-bit Linux. You need the 64-bit one.


TeXstudio: content-assistant popup window is unreadable

I was able to resolve this by changing the style.
Go to Options > Configure TexStudio > General.
Under Style try something besides GTK+ or default. I had success with everything but these two.


Ubuntu helps you to do that in a persistent way with /etc/dpdk/interfaces

I'm not sure if your cards are supported, but for you it could look like:

pci 0000:01:00.0 uio_pci_generic
pci 0000:01:00.1 uio_pci_generic

More can be found at https://help.ubuntu.com/16.04/serverguide/DPDK.html#dpdk-config-dev


Can I use SSD for system and HDD for /home partition w/o problems in future?

Having your system / on SSD and your /home on an HDD is not a problem. I and many others have a setup like this, and it works fine. It allows your system to boot, run, and update quickly using the SSD while allowing you to store much more personal data on the /home using the HDD. More generally, separate / and /home lets you overwrite / with a new installation while not touching the user data on /home/.

As others have commented, having swap on an SSD is less advised. This can require lots of writes to the disk, which may reduce the usable life of the SSD. Also as commented, you probably don't need 32 GB of swap. If you have more than 4 GB of RAM, unless you are doing things that use a bunch of memory, a few GB of swap should be plenty.

Regarding resizing the /home partition, you can't resize it while it is mounted. Running a live CD without the partitions mounted allows you to modify them, as you have mentioned. And as others have commented, your parted output does not show any free space on your HDD.


if you messed with the graphics driver, try

sudo rm /etc/X11/xorg.conf

and see if it bring back the basic UI interface.


Since OTA10 upgrade the battery life of my phone is eaten up by "fitbitaccount"

To quickly stop the mess, I manually removed files about fitbit configuration in phablet accounts:

rm ~/.local/share/accounts/applications/com.canonical.scopes.fitbit_fitbit.application
rm ~/.local/share/accounts/providers/com.canonical.scopes.fitbit_fitbitaccount.provider
rm ~/.local/share/accounts/qml-plugins/com.canonical.scopes.fitbit_fitbitaccount
rm ~/.local/share/accounts/services/com.canonical.scopes.fitbit_fitbit.service

and finally killing the offending process "/usr/bin/online-accounts-ui" using command kill PID or restarting the phone.


This list is by no means exhaustive. I would adivse you to try 2 or 3 of the open source options to understand which suits best your needs.
MythTV
This is the most reputable option for Linux, has been around since 2002 - initially as an alternative to TiVo - and comes with plenty of features. It is released under a GPL licence and available from the Software Centre; detailed install and configuration instructions are available at the Ubuntu Wiki.

Kodi
This is another old guard programme that retains some popularity. Beyond live TV and personal recording, it also provides plug-ins to access streaming services such as YouTube, Amazon Prime or Spotify. Kodi is released under a GPL licence and available from a third party PPA; install instructions are available at the Kodi wiki.

Note: Since you are installing a new system, you might wish to take a look at Kodibuntu. This is an interesting option if you are not intending to do much else with this system.
SageTV
A media centre that existed as a commercial product for about a decade. In 2011 it was acquired by Google, whom opened the code this year under an Apache licence. It counts PVR among its features, but it has not been developed that much since Google bought it. I could not find install instructions for recent releases.
tvtime
This is a less popular TV programme with recording capabilities. The latest release is from 2005 but it seems to still have a relevant number of users.

JRiver
This is a popular proprietary multimedia programme that is almost 20 years old. Among other things, it supports TV recording and keeps a TV station library. It still has a large community around it, an interesting option among the commercial software.
--
Finally, it might be a good idea to write a message to the NextPVR folk asking them for a Linux version, explaining that you will quit using their software if they do not do so.


sudo dpkg --add-architecture i386

sudo apt install libnvidia-gl-450:i386

This solved my problem for those who has the same problem in the future.


What Graphical Logfile Analyzers are available?

There are various log viewers for the desktop environments; gnome-system-log is searchable and user-friendly; as is ksystemlog for KDE (although of course you then need to install the KDE runtime). The gnome log should be the best one for you really, as it can be used to quickly filter the logs and find what you want; you can go straight to syslog, for example, and find the Ubuntu system messages and monitor how the system is working in the background with cron, etc. I recommend log viewing (and then researching things) as a great way of learning how the system works.

Terminal wise, you can watch any open logs in real-time with tail -f <log file> and grep can be very useful to search for words such as 'Machine' 'Hardware' and 'error', which often pop up in faults: for example grep -i 'machine' /var/log/kern.log. With grep it is important to use the i switch to ignore capitalisation, as you can miss important bits of the log without it. To look through a whole folder of logs, you can use grep -ir <folder>.


12.04 server a little bit broken ( dpkg:error processing gconf2 / can't exec md5sum)

I found a solution.

In some way last massive system upgrade apt-get update && apt-get upgrade created the problem with initramfs.

I went into /var/lib/dpkg/info and renamed the file initramfs-tools.postinst. Then I ran apt-get update && apt-get upgrade again, and the system rebuilt and reconfigured/recreated this file and now all seems to be ok.


upgrade 14.04 with errors and shows red sign on top

This can damage stuff. Do not run these commands unless you know what you're doing!

Hi Please try these options

sudo rm /var/lib/apt/lists/* -vf

then

sudo apt-get update

or

sudo apt-get -f install


collect2: fatal error: cannot find 'ld' compilation terminated

In my case I had this resolved with a workaround:

On the cross-compiler bin dir I made a symlink pointing to the compiler

ld (ld -> powerpc-fsl-linux-ld).

Then in the makefile or build script I added the toolchain folder to the PATH variable

export PATH=$PATH:"toolchain-dir-absolute-path"

it worked!


Why don't I have a /usr/local on Ubuntu 16.04?

The linked tutorial has shows the command as:

sudo mv hadoop-2.7.3 /usr/local/hadoop`

There should be no tilde ~ before the file path. Tilde is expanded as your user's home directory, in this case /home/mike/, so you're trying to create /home/mike/usr/local/hadoop rather than /usr/local/hadoop

The following command should work:

sudo mv hadoop-2.9* /usr/local/hadoop

Beware that if you have more than one match for hadoop-2.9* the mv command will fail with a complaint about too many arguments for the command.


Force "bad" (not 0) return code of terminal command?

If you're looking for a system command that always returns a non-zero exit code, then /bin/false seems like it should work for you. From man false:

NAME
       false - do nothing, unsuccessfully

SYNOPSIS
       false [ignored command line arguments]
       false OPTION

DESCRIPTION
       Exit with a status code indicating failure.


Ubuntu 11.04 64bits Keeps Randomly Freezing

I fixed the problem by accident. The problems was actually the SDD. For some reasons, the Drive doesn't perform well when no enough space is left at the end of the last partition for "Garbage Collection." I resized my last partition and left about 1GB left at the end of the drive. I have never got a freeze again.

Solution:

Leave at least 1GB free space at the end of the last partition in your Crucial M4 drive.

It works for me.


So there is a bios option which became enabled for "OS Optimized Defaults" as a result of the recent upgrade.

Once I Disabled this option, and rebooted, my USB drives are now recognized and loaded, restoring the expected behavior prior to upgrading the Ubuntu Operating system.

I am willing to consider other answers which fully explain what entries are or created or modified by the OS and available to BIOS having to do with the following:

Bios Entries to load specific operating systems such as "Ubuntu"
Bios entries for OS Optimized default behaviors and how it gets set or modified
Recognition of boot-able partitions and drive availability at bios startup and how they are identified or loaded in Ubuntu operating systems which may have been created or modified by the upgrade


How do I not resolve unmet dependencies?

I would make a dummy package with equivs that "provides" the dependency without actually providing anything. This may break things if they actually depended on something and you're faking it.

I've already answered this here: How to trick apt dependencies? but you would need to edit the control so that you had a "provides: zeitgeist" line in there somewhere (check the syntax on that too!)


Kubuntu 18.10 Notifications Don't Show Up

Perhaps, you don't have Notification widget anywhere on your desktop. In my experience, notifications wouldn't show up, unless you add Notification widget in system tray panel or on desktop, or wherever it suits you.


Why is this rkhunter script sending empty emails?

Given your additional information in the comments. That script is apparently not the one sending you that email, since the subjects do not match.

Does the empty mail come daily, at approximately the same time each day? (and if so, when?) I'd go to look for other cronjobs running rkhunter. Perhaps an older version of the package installed a different cronjob, and that this didn't get replaced properly by a newer version.

Firstly, see if there are other jobs running rkhunter in cron.daily.

grep -F rkhunter /etc/cron.daily/*

Next place I'd look is in all the different crontabs. First, the user crontabs, look for jobs running at approximately the time you get those emails (man 5 crontab explains the format).

crontab -l      # lists your user's crontab
sudo crontab -l # lists root's crontab

Next, the system crontab:

cat /etc/crontab /etc/cron.d/*

Cron logs to syslog as well, so you could look for lines containing CRON in /var/log/syslog as well.


That weird character, sometimes displayed as ⌷, is the Ubuntu unicode logo, .

Byobu tries to use Unicode symbols, but sometimes those may not display correctly, if you're on a system that doesn't include that character in its font set.  All of Byobu's symbols are tested to display properly on on Ubuntu (with the Ubuntu font) within Gnome-Terminal, but your mileage may vary on other terminals (such as Putty), other Linux systems, Windows or MacOS.

You can disable the logo entirely, by going to the Byobu configuration menu, by either pressing F9 or running byobu-config, selecting, "Toggle Status Notifications", de-selecting "logo", and then pressing "Apply".

And you can toggle all UTF-8 characters on/off by pressing Alt-F5, or running /usr/lib/byobu/include/toggle-utf8.

Full disclosure: I am the author and maintainer of Byobu.


There are two possible ways

Use an icon set with monochrome images for your apps
Use your own custom icons to the icon set

You can create icons for Mega and Telegram and add it to the custom icon pack.

Also, try using Papirus Icon theme. They have a monochrome icon set for task bar. Maybe, Mega and Papirus has icons in it.

https://github.com/PapirusDevelopmentTeam/papirus-icon-theme

PS : You can also use any icon themes with monochrome icons for app of your choice


Low quality window switcher icons in Gnome 3

As evident from the screenshot, the icons for Google Chrome, Terminal and Emacs are fine.

This means that the resolution of icons used in other applications is low. Hence when they are scaled to a bigger size, the quality degrades.

There is no problem in Compiz or any other package.

You can either manually replace the icons with higher resolution/scalable icons or use an icon theme.

Only for example: You can try Faenza Icon Theme. Instructions given on: http://www.liberiangeek.net/2011/11/install-and-enable-faenza-icon-theme-in-ubuntu-11-10-oneiric-ocelot/.


How to make multiple DEs less messy? Specifically KDE on Ubuntu

I think that if you want to experiment with different Desktop Environments it is perhaps best to do that on virtual machines rather than the computer you use all the time.

Each DE installs so many other programs you're bound to get some clashes, and certainly lots of alternative apps you probably don't want (how many office apps do you need?)


Dual booting Ubuntu with Windows 7 on a single hdd with common slaves?

You can actually use single HDD for dual booting without any issue, because both OS will be installed on different partitions.

And as far as mount point goes, you should be able to use "/" as your mount point. This little old but very good official help should give you better idea about partitioning in general in Ubuntu.


Ubuntu Server 14.04: How to keep the state in remote desktop sessions?

For what you are wanting to achieve I think you really need to use NoMachine Enterprise Server see link below. NOTE: I have nothing to do with them, however I researched this about 12 months ago for a client and that was the best option. Alternatively You could look at the Linux Terminal Server Project, or specifically these references here: https://help.ubuntu.com/community/UbuntuLTSP#Linux_Multi-User_Server_Configurations
Although they seem to be for older versions of Ubuntu.

NoMachine Enterprise Server provides multi-node support:

https://www.nomachine.com/enterprise


Ubuntu replaced my /home directory after install

Get the UUID of the partition with blkid and add it to your /etc/fstab as follows (assuming it has an ext4 file system):

UUID=paste_your_UUID_here /home           ext4    defaults        0       2

Then a simple sudo mount -a (or a reboot) suffices to mount it and it is mounted automatically from now on.

An example how you can set a partition's mountpoint in the installation gives this screenshot:

Of course this is different from your case – here the home partition /dev/sda6 is set to be formatted with reiserfs.


Reopen a closed GUI of a running program

This is a result of Canonical's policy not allowing traditional system tray icons anymore, let alone a few exceptions.

Truecrypt and some versions of Skype still use the old-fashioned way of advertising their presence in the background, and to allow such system tray icons to be seen, you can run the following command:

gsettings set com.canonical.Unity.Panel systray-whitelist "['all']"

You may need to log out and in again.

To revert this change:

gsettings set com.canonical.Unity.Panel systray-whitelist "['JavaEmbeddedFrame', 'Mumble', 'Wine', 'Skype', 'hp-systray']"


Can't seem to uninstall Spotify completely?

If you installed it through snap, use

sudo snap remove spotify


how to run php script that export to excel file daily in Ubuntu 16?

Do the following:

Go to /etc/cron.d
Create a file: export
Edit file with following code (change the time when you want to execute your script)

SHELL=/bin/bash
PATH=/sbin:/bin:/usr/sbin:/usr/bin

## Scripts
#00 01 * * * root nice php /path/to/your/php/script


Run a program from a downloaded zip file

You don't have Java Run-time (JRE) installed which is required to run .jar files.

To install JRE, run

sudo apt install default-jre openjdk-8-jre


For those who have this problem and tried any solution they found: I found that setfacl can make problems with permissions on /var/spool/cups folder, so try to disable it:
setfacl -bn /var/spool/cups

or try to set ownership to /var/spool/cups folder
sudo chown -R lp:lp /var/spool/cups

or
sudo chown -R root:lp /var/spool/cups


Use this command for uninstall spotify-client :

sudo apt-get purge spotify-client


First uninstall your samba version :

sudo apt-get purge samba4

sudo apt-get install -f

Second add samba4 repository :

 sudo apt-add-repository "deb http://ppa.launchpad.net/kernevil/samba4/ubuntu precise main"

sudo apt-get update

Third install samba4 dependencies :

sudo apt-get install git build-essential libacl1-dev libattr1-dev libblkid-dev libgnutls-dev libreadline-dev python-dev python-dnspython gdb pkg-config libpopt-dev libldap2-dev dnsutils libbsd-dev attr krb5-user docbook-xsl libcups2-dev libpam0g-dev ntp -y

Fourth download samba4 :

sudo apt-get install samba4


Problem with Display Resolutions after update

I solved this, at least temporarily.

What appears to be the case is some how the the proprietary nvidia drivers do not work with kernel version 3.13.0.43 (at least in my case). This causes the computer to incorrectly identify the two monitors as being a single unit rather then two separate items.

I used the procedure in this post to roll back to 3.13.0.40 and everything works fine.

How Can I Roll Back a Kernel Update?

I will have to wait for an updated driver before I can update my kernel.


How to clear Weather location on Ubuntu 18.04 (GNOME)

Open a terminal and execute this command, it will clear all the locations from gnome-weather:
gsettings reset org.gnome.Weather.Application locations

In case you prefer a GUI solution, you can install and use dconf-editor to achieve the same.
Update : Meanwhile the command has changed ... Thank you @bela83 for your information ! :)
gsettings reset org.gnome.Weather locations


Why's this shutdown one-liner command not working

This:

history -d $((HISTCMD-1)) && echo 'password' | sudo -S shutdown -h 08:00

is not actually a command, it's a fragment of shell script. So you need to have the shell execute it. Something like this:

import os
halt = "history -d $((HISTCMD-1)) && echo 'password' | sudo -S shutdown -h 08:00"
os.system(halt)


Wine is not installing missing dependencies

Run sudo apt-get install -f. This command fixes dependencies. After fixing dependencies, continue according to the tutorial.


Application Menus File,View, etc missing in Gnome-fallback

Okay, so after alot of searching and trying i found a solution to show the hidden application menus in my system.

Please Note: The original gnome-shell, without being tweaked, does not have this issue.

The issue mainly is caused by GlobalMenu which appears to be Not Supported under the Gnome3-fallback mode just yet.

So what I did was Disabling the GlobalMenu and got my Application menus back once again, and here's how i did it:

First, we need dconf-editor so we're going to install dconf-tools

sudo apt-get install dconf-tools

after installing, Press ALT+F2 and Type dconf-editor and press Enter.

now navigate to org/globalmenu and uncheck enabled.

You may either log out and log back in or restart your system and the Application menus will be ready to be used once again.


After a good night's sleep I got Ubuntu to find the SSD. All it needed was adding another parameter: "pci=nomsi"

Thanks for the suggestions to everyone.


Go to System Settings. Click on Multimedia. Click on Phonon.

There is a list of categories on the left side of the window. Click on the following options: Audio recording, Communication, Recording, Control (the last three are under the "Audio Recording" section which is a category itself). Move your device to the top of the list and click Apply.

Then make sure your microphone is unmuted: go to the KMix program and click the "Capture devices" tab. Make sure that the speaker icon at the bottom does not have a red X next to it; if it does, click the speaker icon.


Well the problem was power delivery. For some reason the dock that provides power was not providing it very well; ant the cpu was protecting and locking it's frequency to 400MHz and that's why the load average was climbing really high and the kernel entering panic.


If I make a script that requires root privileges, do I need to put sudo in the script too?

no, if you need root privileges you call the script with sudo.


Power Saving mode after start-up (12.04.4)

I managed to fix my issue. I reinstalled xserver-xorg (sudo aptitude reinstall xserver-xorg). I dont't know how was issue fixed by performing this action, but it's fixed. It would be nice if someone could provide enlightenment regarding this issue and this solution.

If you ask me why I reinstalled xserver-xorg, the answer is because I previously had issues with proprietary graphic drivers, and after I fixed them, I reinstalled xserver-xorg. Everything worked fine until first restart, and the rest is start of this thread. That is the reason for my action.

Again, this is just a solution that helped me solve this threads issue, it might not be recommended or even right, I think I owe an answer since I found one. Cheers.


.deb package creation. Why are my files not being installed?

When I want to verify the contents of a package I have built, I use dpkg-deb to unpack it in a temporary directory.

$ mkdir /tmp/t
$ dpkg-deb -x foo.deb /tmp/t
$ ls /tmp/t

Does the package install successfully or is there an error?  dpkg does not allow more than one package to provide the same file.  If another installed package contains that file then your package will fail to install.  I searched the contents of official packages for ldap.conf[1], and I find /etc/ldap/ldap.conf instead.

You may find dpkg-divert to be useful to you.  I haven't actually used it, but it is there.

[1]: http://packages.ubuntu.com/search?mode=exactfilename&suite=quantal&section=all&arch=any&keywords=ldap.conf&searchon=contents


Wifi disabled, no hardware switch available, rfkill list reads "Hard Blocked" anyway on an Acer Aspire One

I met the same problem with the ACER Aspire One of my daughter.
rfkill list revealed that Wireless LAN is Hard blocked.
Using sudo rfkill unblock 0 (0 referencing Wireless LAN in above list) solved the issue !


GRUB is absent after re-installing Windows XP

Windows will do that: It assumes its the only OS and overwrites the Master Boot Record (MBR).   It's usually easier to install Windows first.  Fortunately its not difficult to fix.  Take a look here

The easiest way is

Insert your Ubuntu CD, reboot your computer and set it to boot from CD in the BIOS and boot into a live session. You can also use a LiveUSB if you have created one in the past.
Install and run Boot-Repair
Click "Recommended Repair".
Now reboot your system. The usual GRUB boot menu should appear. If it does not, hold Left Shift while booting. You will be able to choose between Ubuntu and Windows.


Ubuntu Cloud and MAAS are different things - different layers if you like.

MAAS is a low-level layer which deals with physical hardware. It is for deploying the base level software to a rack of servers quickly and easily. It can then work in conjunction with juju to deploy particular services (e.g. web servers, databases) to that hardware. This could be for all sorts of applications (not just clouds).

"Ubuntu Cloud Live" is really the top-layer full cloud service image, built with OpenStack.

You can find out more specifics on MAAS at maas.ubuntu.com


Nvidia Plugin causing black screen on Ubuntu LTS 18.04

issue these steps

sudo rm  /etc/X11/xorg.conf
sudo apt install --reinstall nvidia-prime # make sure nvidia-prime is installed
sudo prime-select nvidia # switch to nvidia
sudo rm /lib/modprobe.d/blacklist-nvidia.conf /etc/modprobe.d/blacklist-nvidia.conf # remove stray blacklist files
sudo update-initramfs -u # update the initrd
sudo reboot

see further discussion at https://devtalk.nvidia.com/default/topic/1068626/black-screen-after-install-of-nvidia-driver-ubuntu/


How to install new Intel Ethernet driver

Try with installing Common ethernet drivers containing package :

sudo apt-get install linux-image-`uname -r`


I have a problem installing Packet Tracer in Ubuntu 20.04

Install the missing dependencies (dialog and libgl1-mesa-glx):
sudo apt install libgl1-mesa-glx dialog

Or use gdebi:
sudo apt install gdebi
sudo gdebi PacketTracer_731_amd64.deb


"libmtp error : could not send object info." on attempting to access/transfer files from android phone's memory card

I'm not sure if you have solved this but I came across the same issues today.
I was trying to copy music to my Android's phone SD card and I got this error when the file name of the song, not the tag, had 'illegal' symbols in it. I removed the apostrophe and the file copied over.
05 Goodbye 70's.flac change to 05 Goodbye 70s.flac

Hope this helps.


How to create an animated GIF from MP4 video via command line?

ffmpeg 3.4.4 can do it directly on Ubuntu 18.04
You likely want to use something like:
sudo apt install ffmpeg
wget -O opengl-rotating-triangle.mp4 https://github.com/cirosantilli/media/blob/master/opengl-rotating-triangle.mp4?raw=true
ffmpeg \
  -i opengl-rotating-triangle.mp4 \
  -r 15 \
  -vf scale=512:-1 \
  -ss 00:00:03 -to 00:00:06 \
  opengl-rotating-triangle.gif

opengl-rotating-triangle.gif

Image info: 426kB, 45 frames, 512x512 apparent size, coalesced, conversion time on a Lenovo P51: 0.5s.
The above conversion also worked after a ulimit -Sv 1000000 (DRAM usage limited to 1GB), so it does "not consume huge amounts of memory" like previous attempts I  did with Imagemagick which almost killed my machine. 500MB however failed because ffmpeg failed to load its shared libraries... time to upgrade your RAM ;-)?
Test data generation procedure described on this post.
The output has a visible dotting pattern, which is not as visible in "ffmpeg + convert" method below. We can try to improve the image quality with methods described at:

https://superuser.com/questions/556029/how-do-i-convert-a-video-to-gif-using-ffmpeg-with-reasonable-quality
https://stackoverflow.com/questions/42980663/ffmpeg-high-quality-animated-gif

E.g. using the palettegen filter:
ffmpeg \
  -i opengl-rotating-triangle.mp4 \
  -r 15 \
  -vf "scale=512:-1,split[s0][s1];[s0]palettegen[p];[s1][p]paletteuse" \
  -ss 00:00:03 -to 00:00:06 \
  opengl-rotating-triangle-palettegen.gif

opengl-rotating-triangle-palettegen.gif

Image info: 979K, 45 frames, 512x512 apparent size, coalesced, conversion time on a Lenovo P51: 3.5s.
So we see that:

the dotting pattern is much less visible now
GIF size roughly doubled. TODO: why does simply choosing a palette increase the image size? Is it because now more colors so we need more bits per color? How to observe each palette?
generation time was 7x slower, presumably because ffmpeg is first scanning through the entire video to determine an optimal palette

We could also play with documented palettegen parameters like palettegen=max_colors=16 to achieve different size quality trade-off points.
Argument breakdown

-ss 00:00:03 -to 00:00:06: start and end time to cut the video from.
No, GIFs are not the best way to pirate distribute videos online.
See also: https://stackoverflow.com/questions/18444194/cutting-the-videos-based-on-start-and-end-time-using-ffmpeg

-vf scale=512:-1: make the output 512 pixels in height, and adjust width to maintain the aspect ratio.
This is a common use case for images for the web, which tend to have much smaller resolution than video.
If you remove this option, the output GIF has the same height as the input video.
The original video height can be found for example with ffprobe: https://superuser.com/questions/595177/how-to-retrieve-video-file-information-from-command-line-under-linux/1035178#1035178 and is 1024 x 1024 in our case.

-r 15: sampling FPS.
For example, the original video was 30 FPS, so -r 15 means that ffmpeg will pick one frame in every 2 (= 30 / 15).
The perceived output FPS is adjusted to match the input however, so you won't notice a speedup, only greater granularity.
The input FPS can be found with ffprobe, and the total number of input frames can be found with mediainfo as explained at: https://superuser.com/questions/84631/how-do-i-get-the-number-of-frames-in-a-video-on-the-linux-command-line/1044894#1044894
I recommend this option because video formats usually have a higher framerate due to the larger resolution. With smaller GIFs, the lower framerate is less noticeable, and so we can skip some frames and make smaller GIFs.

Video camera footage example
If you want to see the result quality of a video camera video from Wikimedia Commons with a similar command:
wget https://upload.wikimedia.org/wikipedia/commons/f/f9/STS-132_Liftoff_Space_Shuttle_Atlantis.ogv
ffmpeg -i STS-132_Liftoff_Space_Shuttle_Atlantis.ogv -r 15 -vf scale=512:-1 \
  -ss 00:00:17 -to 00:00:22 STS-132_Liftoff_Space_Shuttle_Atlantis.gif

STS-132_Liftoff_Space_Shuttle_Atlantis.gif

Image info: 1.3MB, 75 frames, 512x288 apparent size, coalesced (has minimal effect however, because footage pans slightly from the start), conversion time on a Lenovo P51: 2.3s.
Here is a version with palettegen but only 2 seconds to fit the 2MiB upload limit:

Image info: 1.5MB, 30 frames, 512x288 apparent size, conversion time on a Lenovo P51: 43s.
A more direct:
sudo apt-get install ffmpeg
ffmpeg -i in.mp4 out.gif

also works, but the output GIF would be way larger than the input video, because video formats can compress more efficiently across frames with advanced algorithms, while GIF can only does a simple rectangular frame diff.
Before pre 18.04: ffmpeg + convert one-liner without intermediate files
ffmpeg could not handle GIF previously. The best I had was something along:
sudo apt-get install ffmpeg imagemagick
ffmpeg -i opengl-rotating-triangle.mp4 -r 15 -vf scale=512:-1 \
  -ss 00:00:03 -to 00:00:06 -f image2pipe -vcodec ppm - |
  convert -deconstruct -delay 5 -loop 0 - opengl-rotating-triangle-image-magick.gif

opengl-rotating-triangle-image-magick.gif

Image info: 995kB, 45 frames, 512x512 apparent size, coalesced.
For the Atlantis shuttle footage, and analogous:
ffmpeg -i STS-132_Liftoff_Space_Shuttle_Atlantis.ogv -r 15 -vf scale=512:-1 \
  -ss 00:00:17 -to 00:00:22 -f image2pipe -vcodec ppm - |
  convert -deconstruct -delay 5 -loop 0 - STS-132_Liftoff_Space_Shuttle_Atlantis_512x.gif

produced better looking output, but the final GIF was considerably larger at 6.2MB, so I can't upload it.
Explanation of some of the arguments:

-loop 0: add the Netscape Gif extension Loop count field to the output. 0 means infinite loop as described at: http://www.vurdalakov.net/misc/gif/netscape-looping-application-extension eog, firefox and chromium all loop infinitely by default even without it, so I'm not sure how necessary it is anymore.

-delay 5: time waited before showing the next frame, in hundreths of second, as described at: https://en.wikipedia.org/wiki/GIF#Animated_GIF byte 324. So 100 means 1 FPS, 5 means 1 / 0.5 == 20FPS.

-deconstruct: compress across frames with rectangular diffs, see also: how can I resize an animated GIF file using ImageMagick?

Even if you reduce the height and framerate, the output GIF may still be larger than the video, since "real" non-GIF video formats compress across frames, while GIF only compresses individual frames.
A direct:
convert input.mp4 rpi2-bare-metal-blink.gif

worked, but almost killed my computer because of memory overflow, and produced an ouptput 100x larger for my 2s 1Mb input file. Maybe one day ImageMagick will catch up.
See also: https://superuser.com/questions/556029/how-do-i-convert-a-video-to-gif-using-ffmpeg-with-reasonable-quality
Tested on Ubuntu 17.10.
Gifski
https://gif.ski/
This is another option that was brought to my attention and which claims intelligent algorithms, so let's try it out.
First we need to convert the video to a sequence of images, and then feed that into gifsky, e.g.:
sudo snap install gifski
mkdir -p frames
ffmpeg \
  -i opengl-rotating-triangle.mp4 \
  -r 15 \
  -vf scale=512:-1 \
  -ss 00:00:03 -to 00:00:06 \
  frames/%04d.png
gifski -o opengl-rotating-triangle-gifski.gif frames/*.png

opengl-rotating-triangle-gifski.gif

Image info: 954K, 45 frames, 512x512 apparent size, not coalesced, conversion time on a Lenovo P51: 4.8s.
And the 2s STS:

Image info: 1.6M, 30 frames, 512x288 apparent size, not coalesced, conversion time on a Lenovo P51: 2.8s.
So for me, subjectively, this did not appear to offer significant benefit over ffmpeg's palettegen.


Computer restarted during upgrade now I can't log in, how do I fix it?

I suggest you to backup your data from Live CD and reformat and install a clean ubuntu


How can I get an exact copy of Ubuntu's default /etc/crontab file from any official (local or remote) repository?

on my ubuntu 20.04 desktop the /etc/crontab content is as follows
koen@hpubuntu:/etc$ cat crontab
# /etc/crontab: system-wide crontab
# Unlike any other crontab you don't have to run the `crontab'
# command to install the new version when you edit this file
# and files in /etc/cron.d. These files also have username fields,
# that none of the other crontabs do.

SHELL=/bin/sh
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin

# Example of job definition:
# .---------------- minute (0 - 59)
# |  .------------- hour (0 - 23)
# |  |  .---------- day of month (1 - 31)
# |  |  |  .------- month (1 - 12) OR jan,feb,mar,apr ...
# |  |  |  |  .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat
# |  |  |  |  |
# *  *  *  *  * user-name command to be executed
17 *    * * *   root    cd / && run-parts --report /etc/cron.hourly
25 6    * * *   root    test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.daily )
47 6    * * 7   root    test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.weekly )
52 6    1 * *   root    test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.monthly )
#

instead of changing the /etc/crontab file you coudl also consider adding files in some directories

a file in /etc/cron.d/ with a cron snippet
an executable (script) in the relevant /etc/cron.[hourly |daily |weekly |monthly] directory.

dpkg -S can help to find the package linked to some source
 > dpkg -S "/etc/crontab"
   cron: /etc/crontab

it seems the code can be found here : https://git.launchpad.net/ubuntu/+source/cron/tree/debian/crontab.main


Shotwell is a feature full, yet easy to use, photo manager for the Ubuntu desktop.

Default under Ubuntu

It is the best, and it just works(for me).

Feature list

Supported photo and video formats

Shotwell supports JPEG, PNG, TIFF, BMP and RAW photo files as well as video files.

Importing Photos

Importing from F-Spot

Shotwell can import all your photos and tags from the F-Spot photo manager.

Importing from a camera

Copy photos from a digital camera.

Importing from a memory card

Import photos from a digital camera's memory card.

Importing from your hard disk

Import photos that are already saved on your computer.

Viewing Photos

Basic and extended information

View more detailed information about photos, like the exposure mode used by the camera.

Photo views

Learn about different ways of viewing your photos: in a grid, filling the main window, or filling the whole screen.

The sidebar

The sidebar on the left of the window lists various views of your library.

Organizing Photos

Events

Group photos together that were taken at the same time. Learn how to rename, merge, and sort events.

Flagging photos

Flag photos to mark them as special or to work with them as a set.

Ratings

Give photos a rating between 1 and 5 stars. You can reject bad photos, hiding them from view.

Removing and deleting photos

Remove photos from the library, or delete them from your computer entirely.

Searching

Find photos and videos in your collection by a variety of criteria.

Tagging photos

Organize photos by labelling them.

Titles

Give titles to your photos.

Editing Photos

Adjust the time and date of photos

Change the time and date of photos if those details are incorrect.

Auto-enhance

Let Shotwell improve the brightness and contrast of a photo automatically.

Color adjustments

Change the exposure, saturation, tint, and shadows of a photo.

Cropping

Improve the composition of a photo by cutting out parts of it.

Edit photos with an external program

Use a different program to edit a photo.

Removing red-eye

Correct photos where people have red eyes because of the camera's flash.

Rotate or flip a photo

Click the Rotate button, or choose one of the commands in the Photo menu.

Straighten photos

Straighten a photo so that its horizon appears level.

Undoing changes

Return a photo to its original, unedited form.

What happens to the original when I edit a photo?

Shotwell is a non-destructive photo editor - it does not modify your original photos.

Sharing Photos

Exporting photos

Copy photos out of Shotwell so you can put them somewhere else.

Printing

Click File ▸ Print. For more printing options, select the Page Setup tab in the Print dialog.

Publishing to the Web

Publish photos to Facebook, Flickr, Picasa Web Albums, or other sites.

Sending photos

Send photos via email, instant messaging or in other ways.

Set a desktop background or slideshow

Set your desktop background to a single photo or to a slideshow of photos.

Slideshows

Watch a slideshow of your photos.

Other Features

Missing photos

If Shotwell can't find a photo in your library, it marks it as missing.

Multiple libraries

You can open Shotwell with a different photo library by using the command line.

Photo files

Keep the Shotwell library in sync with photo files on disk.

Plugins

Extend Shotwell's functionality dynamically.

RAW support in Shotwell

More about RAW support in Shotwell.


Run command on another(new) terminal window

This might be what you search:

gnome-terminal -e "bash -c \"!!; exec bash\""

or (shortly):

gnome-terminal -x sh -c "!!; bash"

It opens gnome-terminal with your last command (!!) executed and it stays open with the command output in the shell, even with an interactive command like top or less...

In your case its:

gnome-terminal -e "bash -c \"apropos editor; exec bash\""

or

gnome-terminal -x sh -c "apropos editor; bash"


Wird Chrome service slows down my system (12% CPU usage) and makes it unusable?

This could help:

Disable Add-Ons

Right-click the title bar or press "Shift-Esc" to open Task Manager in Google Chrome. Click "CPU" to see which task is consuming the most resources.
Write down the name of the task if it's a plug-in or extension. Select the process and then click "End Process" to close the task.
Open "Settings" from the Chrome menu and then click "Extensions," or type "chrome://plugins" (without quotation marks) into the address bar and then press "Enter," depending on which type of add-on is exhibiting high CPU usage.
Locate the appropriate extension or plug-in in the list. Uncheck "Enabled" or click "Disable" to prevent the add-on from running.

OR

Reset Google Chrome

Click the Chrome Menu on the toolbar and then click "Settings."
Select "Show Advanced Settings" from the bottom of the page and then click "Reset Browser Settings."
Click "Reset" to revert your browser configuration to default.


how to edit "Xorg.conf" to work with ATI HD 5770?

I m using same card too.
There is no problem with 11.04 and 11.10.

Only these commands and reboot:

sudo apt-get install fglrx
sudo reboot

After restarting, please type to terminal:

env LC_ALL=C amdxdg-su -c amdcccle

It will open Catalyst Control Center window:


How can I get a Canon MB2720 working in Ubuntu?

MB2320 has Linux drivers.  I don't know how similar the devices are though.

At this link click on "Drivers and Downloads", then "Linux" in the drop down box, not "Linux 64 bit" or "Linux 32 bit".


RTL8723AE wireless needs a better driver, my attempt to fix made it worse

Compiling this driver helped: https://github.com/lwfinger/rtlwifi_new

make
sudo make install


How to enable Desktop Settings > Wallpaper > Layout in Kubuntu 16.04

In order to enable the option "folder view", before doing those steps you must set up the option "unlock widgets". To do that click with the right button in a widget, for instance where you have the date, and chose "unlock widgets".

After that, the steps you have mentioned shall work.


Ubuntu 12.10 Bose Companion 5 not working

The solution was to unmute a volume control in alsamixer. In simple steps:

Open a terminal
Type alsamixer, hit Enter

A sort of GUI will be presented.
Press F6 and select 'Bose'.
Increase the volume on the PCM channel using the arrow keys.

I am not sure it is the right volume control, since there was no master and all.

More details are here: Howto- Resolve Nosound Problem On Ubuntu 12.10, 12.04 And Older


I had the same problem with LyX 2.1.4 on Xubuntu 16.04.1.  There appears to be various solutions to this:

Some suggest running the application with the -style gtk+ or -style gtk flags on the command line.
Others suggest setting the environment variable QT_STYLE_OVERRIDE to either GTK, or GTK2, or GTK3.
What worked for me personally was to edit ~/.config/Trolltech.conf (or /etc/xdg/Trolltech.conf) and add the following:

[qt]
style=GTK+

Further discussion on the ArchWiki.


Lately i've been able to use command rar to compress files in shell. Dunno if it was an update period of the package which led it to be unavailable.
Thanks Novice for the RAR Archive Ubuntu. guide


This is because you don't have systemstat.sh in your current directory .. The dot means the "current directory" or "working directory". If you do ls . you will notice that the script isn't there. For running this script you should either use:

the full path /path/to/script/systemstat.sh
copying them to a bin directory cp systemstat.sh /usr/local/bin/ then run without the dot: systemstat.sh
Or adding the directory where the script is to the path PATH=/path/to/script:$PATH and then execute the script without the dot.
or move your working directory to were the script is cd /path/to/script && ./systemstat.sh


Heroku Toolbelt install - header over 360 characters

install-ubuntu.sh adds /etc/apt/sources.list.d/heroku.list. However, it adds http://... instead of https://.... Change that to https.

I downloaded install-ubuntu.sh, added an s to the script, and then ran it. it's at least moving past that step now.


Ubuntu unresponsive with high latency after clean-install of 18.04

From the comments...

User had nomodeset enabled in GRUB, for an unknown reason, thereby disabling the video subsystem software.

Removing nomodeset fixed the problem.


You can use LAMP (Linux-Apache-Mysql-PHP) and you can install it from here


The line phablet-flash (cdimage-touch|cdimage-legacy|ubuntu-system|community) -b actually means chose one of the commands in brackets.

Your correct command is likely to be:

phablet-flash cdimage-touch -b