Jus12's questions

I have three monitors side by side and I have found the following shortcuts in Gnome

1. Shift+Super+Left (move to left monitor)
2. Shift+Super+Right (move to right monitor)

Unlike Unity, nothing happens when I use the shortcut to move left on a window already in the leftmost monitor. In Unity, it moves back to the rightmost monitor (i.e., the rightmost monitor is considered at the left of the leftmost monitor, like the "wraparound" feature in a video game). Can I get the Unity-like wraparound in Gnome for both shortcuts?

I am dual booting Ubuntu 16.04 and 20.04. I don't use 16.04 much anymore and its just there because I haven't got around to removing it.

Every time Ubuntu 20.04 updates, it resets my BIOS boot settings to boot 16.04 by default. Why does it do it and how to prevent it?

EDIT: More details:

1. Booting in uEFI mode (secure boot disabled)
2. Asrock Z390 Taichi motherboard with Intel core-i5 9400F CPU (no integrated graphics)
3. RTX-2070 Rev. A GPU with driver: nvidia-driver-450 (proprietary, tested)

I have a USB extension hub with the following specs (ASCII art is worth 10000 words):

                  ----------------------- 
                  |                     | 
                  |               [Type A female] -> output 1
   Input -> [Type A female]       [Type A female] -> output 2
                  |               [Type A female] -> output 3
                 LED              [Type A female] -> output 4
                  |                     | 
                  ----------------------- 

I have the following cables cables:

1. (Type A male) <--> (Type A male)
2. (Type C male) <--> (Type A male)
3. (Type C male) <--> (Type C male)

My Ubuntu box has both Type A and Type C female connectors. I also have an external SSD that has a Type C female connector.

The combination of cable 2, my Ubuntu desktop and the hub does not work. In summary, the following combinations have been tried:

 | Cable # | Cable side one   | Cable side two   | works? | Conclusion          |
 --------------------------------------------------------------------------------
 |    1    | Desktop Type A   | USB hub input A  | yes    | USB hub works       |      
 |    2    | Desktop Type C   | USB hub input A  | No     | ???                 |
 |    2    | Desktop Type A   | SSD input C      | yes    | Cable #2 works      |     
 |    3    | Desktop Type C   | SSD input C      | yes    | Desktop Type C works|

The table shows that alone each of the three work (Desktop Type C, USB hub and Cable #2). However, the combination does not. What could be the reason?

Long story short: I have MX master 2s mouse whose thumb button sends <ctrl><alt><tab>.

I want to remap the thumb button to <ctrl> but that does not seem to be possible because there are no supported software for linux.

Hence I would like to do the next best thing, which is to try to remap <ctrl><alt><tab> to <ctrl> and hope it works.

Is there any way to achieve what I want?

OS: Ubuntu 20.04 with Unity

I have the following setup:

 ______________
|              |  
| Ubuntu 16.04 |NIC1---(WIFI)---ISP1 (slow, unmetered)-----
|              |
|     game     |
|              |
|  cloud sync  |NIC2---(RJ45)---ISP2 (fast, metered)-------
|______________|

1. I want to use WIFI for certain apps such as cloud sync because its unmetered (ISP1).

2. I want the game and some apps to use RJ45 interface because its fast (ISP2).

For sake of simplicity, lets say Firefox is in category 1 (slow, unmetered), and Chrome in category 2 (fast, metered).

How do I go about doing what I want? We can assume that every application in type 1 has a proxy configuration for accessing internet.

One way I thought would be to run a Squid proxy server on the same box and then use proxy for category 1 apps. The proxy would be configured to use only NIC1.

Would that work? (If so some tips on setting up Squid will be helpful.)

What are some other way to do what I want?

So recently Dropbox stopped syncing symlinks (bad move IMHO). I have a rather small hard drive and use symlinks to sync folders on Dropbox. Recently this stopped working (any new files added to symlinked folders does not get uploaded anymore but older files remain).

I want to continue using my dropbox client to span multiple drives, which I had earlier done using symlinks. Now since these don't work, I want to fool the Dropbox client to thinking they are legitimate folders. I tried mound -o bind but that does not work either.

What other methods could I try?

EDIT: mount -o bind does not work as it results in 0 byte files on Dropbox website and other clients, so the contents of such folders are also not synced.

Using Ubuntu 16.04

I am trying to a salvage an old scratched DVD by ripping it to ISO. I have two readers and created an ISO from each. Each reader is unable to read certain different bytes of the DVD and replaces them with 0s. When I compare the files using cmp -l file1.iso file2.iso, I see that certain bytes on the left are 0 while certain other bytes on the right are 0 (the corresponding bytes on the other files are non-zero). I want to create a 3rd file, say file3.iso that merges the non-zero differing bytes from the above two files. As an example, assume for simplicity that each file has 6 bytes as follows

file1.iso   file2.iso
---------   ---------
0           0
1           1
2           0
3           0
0           4
0           5

file3.iso should be as follows:

0
1
2
3
4
5

The files are quite large (around 8GB). Each file has the same number of bytes. I am using Ubuntu 16.04

Can anyone suggest the easiest way to do what I want. I can use the output of cmp -l as intermediate data but want to avoid writing code.

I have a pure Ubuntu laptop (no dual boot). Today when I restarted, suddenly grub menu started showing. After I select Ubuntu, it boots boots as normal. So my questions are:

1. Why did it start appearing all of a sudden?
2. How do I hide it?

EDIT: output of cat /etc/default/grub:

# If you change this file, run 'update-grub' afterwards to update
# /boot/grub/grub.cfg.
# For full documentation of the options in this file, see:
#   info -f grub -n 'Simple configuration'

GRUB_DEFAULT=0
GRUB_HIDDEN_TIMEOUT=0
GRUB_HIDDEN_TIMEOUT_QUIET=true
GRUB_TIMEOUT=10
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
#GRUB_CMDLINE_LINUX_DEFAULT="acpi=noirq"
#GRUB_CMDLINE_LINUX_DEFAULT="acpi=force"
GRUB_CMDLINE_LINUX_DEFAULT=""
#GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi=force"
#GRUB_CMDLINE_LINUX="acpi=force"
GRUB_CMDLINE_LINUX=""
#GRUB_CMDLINE_LINUX="acpi=noirq"

# Uncomment to enable BadRAM filtering, modify to suit your needs
# This works with Linux (no patch required) and with any kernel that obtains
# the memory map information from GRUB (GNU Mach, kernel of FreeBSD ...)
#GRUB_BADRAM="0x01234567,0xfefefefe,0x89abcdef,0xefefefef"

# Uncomment to disable graphical terminal (grub-pc only)
#GRUB_TERMINAL=console

# The resolution used on graphical terminal
# note that you can use only modes which your graphic card supports via VBE
# you can see them in real GRUB with the command `vbeinfo'
#GRUB_GFXMODE=640x480

# Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux
#GRUB_DISABLE_LINUX_UUID=true

# Uncomment to disable generation of recovery mode menu entries
#GRUB_DISABLE_RECOVERY="true"

# Uncomment to get a beep at grub start
#GRUB_INIT_TUNE="480 440 1"

I followed this answer to the question of removing Ubuntu documentation to save space. While the method worked, it has rendered my system somewhat broken. Every now and then when I install some package, it depends on some folder in the documentation existing. Two such apps are:

1. Virtual Box (error during run -- had to create /usr/share/doc/virtualbox)
2. PostgreSQL (error during installation -- had to create /usr/share/man/man7)

EDIT

It took a lot of digging (around 2 days) to find solution to 1. Unfortunately, there was no way to find out which directory was the issue, or even that the existence of the directory was the issue. Fortunately, after 2 days, just before I was about to do a clean install, I came across this post that hinted that removing the documentation could be the problem.

So the solution is not just to "recreate the folder", as one of the comment says, but to find out which folder(s) to recreate, which is not so easy.

2 was easier due to the error printed on console.

For now I would like to get my system back to the "unbroken" stage without having to do a complete reinstall. What is the best way to get documentation back?

I am using TexMaker and I want to map CTRL-Q to "Comment" and CTRL-W to "Uncomment". I do not want to disable CTRL-Q, but to change its default behavior.

In TexMaker, I get the following error on console:

QAction::eventFilter: Ambiguous shortcut overload: Ctrl+Q
QAction::eventFilter: Ambiguous shortcut overload: Ctrl+W