Simon's questions

I have installed Ubuntu alongside with Windows 10, and they are on different disks. Since the disk containing Windows does not have a UEFI partition and uses C:/EFI/Microsoft/Boot/bootmgfw.efi to load Windows instead, grub does not recognize the Windows bootloader.

If I boot from Ubuntu install USB and enter the grub command line, by running the following commands I can start Windows successfully:

chainloader (hd1,msdos1)/EFI/Microsoft/Boot/bootmgfw.efi
boot

However, if I enter the grub command line of the installed Ubuntu on disk, when I run:

chainloader (hd1,msdos1)/EFI/Microsoft/Boot/bootmgfw.efi

it print Error: invalid signature. If I add --force option to chainloader and then boot, the screen goes blank and windows does not start up.

Can anyone give some suggestions on how to boot Windows from Ubuntu grub?

In firefox, if I move my mouse to extreme right of the screen and do left click, the scroll bar will respond to this click. But this function does not hold for all applications. Is there any possible way to bring this function to other applications?

In fact, what I need is to achieve this function in Foxit Reader. Instead of adopting the system window style, Foxit Reader has its own UI, so I think simply change the desktop theme may not help and some tweak with X-server will be needed. By the way, I am using ubuntu 20.04 with gnome.

I am using ubuntu 20.04 and the default kernel version is 5.4.0-42 and 5.4.0-58. For some reason, I have upgraded my kernel to 5.8.0-36 several days ago with the command sudo apt install linux-image-5.8.0-36-generic. But now the kernel version has automatically upgraded to 5.4.0-40 and I was not notified. How can I stop the automatic upgrading?

I am using ubuntu 20.04 on a machine with 16G RAM and 1T SSD. I used to have a swap partition of 20G and know how to hibernate with swap partition. But I found the partition never used in normal time. So I think it is unreasonable to preserve a swap only for hibernation and I deleted this partition and decided to hibernate with hibernation file. But I am stuck in doing this, even found some answer saying this is impossible. So is there any way to achieve hibernation without swap partition?

The following link would be helpful but I can not understand it fully, https://help.ubuntu.com/community/SwapFaq.

I am using Ubuntu 20.04 on Dell vostro 7500. But the whole system crash frequently. The symptom is the screen shows no response to keyboard event and mouse event(mouse cannot move or click), but the screen is still light and showing the graphic contents(but everything including the time is stuck). SysRq+REISUB, which works in normal time on my machine, is invalid when crashing. And /var/log/syslog contains nothing after the crash. So it should be a kernel crash. Does anybody encounter this problem ever? I have reported this on launchpad https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1909381. Please vote on it if you also share the same problem.

After the crash, I updated my BIOS and fully tested my hardware and found no hardware error. Switching my kernel from 5.4.0-58-generic back to 5.4.0-42-generic also does not solve this problem.

I searched the contents in syslog just before the crash, but I found no much similar pattern. But the following line appears before both of the two crashes:

Dec 22 19:09:12 ofSimon kernel: [  878.796035] sof-audio-pci 0000:00:1f.3: error: no reply expected, received 0x0

I do not know what it means, and I noticed that this line also appear in tty every time when I shutdown my computer. Can anyone explain it to me?

To achieve a low-level swap of left ctrl key and capsLock key, I used xkbcomp as follows:

First get the present keyboard layout:

 xkbcomp $DISPLAY output.xkb

Then I change the 2 lines in output.xkb from

<LCTL> = 62;
...
<CAPS> = 66; 

to

<CAPS> = 62;
...
<LCTL> = 66;

Then run

xkbcomp output.xkb $DISPLAY

to take it into effect. It works perfectly in most desktop applications. But the problem is with vscode. Actually it also works well in the normal mode of vscode, but when I try to change a shortcut in vscode and it prompt me to press new keys to change the shortcut, I pressed the capsLock key on my keyboard and vscode thinks that I pressed ctrl+capsLock simultaneously. This is not what I expected, vscode should not know my capsLock key, it should only know I pressed ctrl key because XServer should only tell vscode that I pressed ctrl key. I think it is because my configuration is not complete so that vscode could still detect my capsLock key. Can anyone tell me how to do a complete swap of ctrl and capsLock? xmodmap should not be the solution because it is based on xkbcomp and with limited function.

My system is Ubuntu 20.04, I download nemo-preview from the repository of Linux Mint and installed it manually. No error or warning shows in the installation. But nemo-preview does not function when I open nemo.

I run nemo-preview in the command line, and it shows the following information and then exit.

(nemo-preview-start:20719): Cjs-WARNING **: 14:03:55.707: JS ERROR: Error: Requiring NemoPreview, version none: Typelib file for namespace 'GtkSource', version '3.0' not found
@/usr/share/nemo-preview/js/ui/fallbackRenderer.js:31:7
@/usr/share/nemo-preview/js/ui/mimeHandler.js:28:7
@/usr/share/nemo-preview/js/viewers/image.js:38:7

Segmentation fault (core dumped)

And the content in /usr/share/nemo-preview/js/ui/fallbackRenderer.js:31:7 is

const NemoPreview = imports.gi.NemoPreview;

Does anyone know how to fix this problem?

When opening nautilus, choose a file and click ctrl+c copy the file into clipboard so that I can paste it in somewhere else in nautilus. And if the file is an image, I can even paste it in libreoffice. I want to know whether I can achieve the same effect as ctrl+c in command line without opening nautilus?

I am using ubuntu 20.04, and my problem is that the network connection sometimes terminate. I want to reconnect to the same network, but when I click the wifi icon at the header bar and choose "Select Network", it only permit me to change to another network, otherwise the button "connect" is gray. So I have to open gnome-control-center to reconnect the network, but gnome-control-center is really slow to start, it takes 3+ seconds to open. So I wonder how I can simply reconnect to the present wifi without opening it.

My current wifi connection is WPA2 and require both a username and a password, which has already be save in gnome-control-center. Reconnecting by either terminal or GUI is ok, but I do not want sudo, because entering password is time costly.

By the way, can anyone explain why gnome-control-center startup is that slow?

I had opened 6-7 application(the memory is 16GB) on ubuntu 20.04, just as I opened a new tab in firefox, the whole screen was stuck-up. The screen was still showing the GUI of firefox, but when I moved mouse or pushed keyboard, the screen did not change anything(and the keyboard would light up when I push a key, but the keyboard light is set to off in my seesion). I tried Alt+F2, Alt+Ctrl+F1-7 and Alt+Ctrl+Fn+F1-7, none of these brought any change to the screen.

I have also tried SysRq key, but I am not sure which key is SysRq on my machine(Dell vostro 7500).

Now I have powered off my machine and restarted it, but I do not want to do this every time when I encounter this problem(this problem has happened several times).

I want to know whether there is a way to use super(win) key alone as shortcut without change its function as a modifier.

On ubuntu, by default, pressing and then releasing super key, without pressing other keys, will invoke activity overview. But I want it to invoke a shell script written by me. And when super key and other key are pressed simultaneously, I want it to function as before.

I know how to disable super key from invoking activity overview in dconf-editor, but I do not know how to remap it.

In short, I want to map Ctrl+H/L to Ctrl+Left/Right without autokey, and xbindkeys+xdotool/xvkbd does not work. Details are as follows:

I am now using autokey to achieve the mapping, it works very good, but in some application it fails to work because autokey is a high-level application. So I want to achieve a low-level key map.

Application such as xmodmap and xkb cannot do this because Ctrl+Left/Right is not a keysym. I have tried xbindkeys+xdotool. The following configuration script for xbindkeys does not work:(to simplify the question, I map the keys to 'a' instead Ctrl+Left/Right)

#.xbindkeys
"xdotool key a"
Control+h

I think it is because the pressed keys influence the execution of xdotool, because the following works:

#.xbindkeys
"xdotool key --clearmodifier a"
Control+h+Release

But I just do not want to trigger the command when I release the key, I want it to take into effect immediately when I press the key, so I change the configuration to:

#.xbindkeys
"xdotool keyup h; xdotool key --clearmodifier a"
Control+h

This configuration still works, but it cannot achieve autorepeat, that is when I press the key board without release for a long time, the command only execute one time. I have also tried xvkbd but is does now work:

#.xbindkeys
"xvkbd -text 'a'"
Control+h

Can anyone give me some help to achieve my key map?