the PC running Gentoo Linux was working fine until yesterday. Today he begins the boot checkup until he arrives at:

[   ok   ] Reached target multi-user.target.
[   ok   ] Reached target graphical.target.
[   17.218749] (udev-worker) (293) used greatest stack depth: 12504 bytes left

And then it halts. Here is a photo of the full screen when this happens: this seems to be a problem with udev-worker using all the memory available to it, does this means that I should free more disk memory for the system or for the swap partition? Any answers that do not involve formatting the system and installing Gentoo (or some other distro) are welcomed ( I really want to leave formatting this PC as a last resort.).

I have read some fascinating threads about the history and implementation of the halt and shutdown commands (and equivalents, eg. runlevels and systemctl targets) across different versions of Unix(-like) OSes/Linux over the past several decades, and it has been made abundantly clear that the purpose, use cases, and implementation of halt/shutdown and the relationship between the two has and still does vary from distribution to distribution. Having said that, I have a very specific question: **are there any current/modern practical use cases for (directly) using halt implementations that shut down the OS to a non-responsive/non-existent state (ie. not even a single-user shell) and leave the computer system itself powered on?** I'm asking because I would imagine most modern hardware would have a software mechanism for powering off, so I can't conceive of a need to halt an OS before manually powering off/restarting a system. (If I am wrong in saying "most", or if there is in fact a benefit to manually powering off/restarting a system with the OS terminated, please share.) I've also read that halt could be used for 'performing maintenance' on a computer system that is still powered on, but I haven't seen this point elaborated on - what kind of 'maintenance' could be done (and would be beneficial to do) on a powered-on computer system that doesn't have an OS (or any other software interface like BIOS) running? For reference, these are the more useful threads I've read on the halt vs shutdown discussion, though they haven't really discussed modern uses for halt implementations that shutdown the OS without powering off the system: - https://unix.stackexchange.com/questions/8690/what-is-the-difference-between-halt-and-shutdown-commands/196471 - https://unix.stackexchange.com/questions/42572/is-halt-the-same-as-shutdown-h-and-poweroff-the-same-as-shutdown-p - https://unix.stackexchange.com/questions/467742/how-exactly-a-shutdown-h-halt-differ-from-normal-shutdown-in-linux - https://unix.stackexchange.com/questions/8690/what-is-the-difference-between-halt-and-shutdown-commands

I have a shell script that loops over files. Processing each file can take several hours (it is CPU/GPU-limited). Sometimes I want to pause the execution at the end of a loop, when a file is finished processing, but then be able to resume later on, similar to how you can pause using ctrl-z and then fg, but I want it to finish the current loop before actually pausing/going into the background. Basically I want the script, when it receives a ctrl-z (or similar), to wait until it reaches a certain line before it halts. How do you achieve that?

How can I check (in a safe way) if the current user has the permissions needed to shutdown the system on Unix & Linux? I'm writing a script that needs to check to see if the current user has the permission needed to shutdown the system. But, of course, I want to determine this *before* actually attempting to shutdown the system. Ideally, I'd like a solution that works on as many Unix & Linux distros as possible. What can I execute in my script to check to see if the current user has permission to shutdown the system?

About halt in Linux in these places: * [What is the difference between the shutdown, halt and reboot commands?](https://superuser.com/a/236912/1024056) * [Understanding Shutdown, Poweroff, Halt and Reboot Commands in Linux](https://www.tecmint.com/shutdown-poweroff-halt-and-reboot-commands-in-linux/) * [What is halt command in Linux?](https://frameboxxindore.com/other/what-is-halt-command-in-linux.html) Indicate the following: halt is usually to get to a state where you can perform low level maintenance. and You can use it to get the system to a state where you can perform low level maintenance. Therefore: What does _"you can perform low level maintenance"_ mean? Some examples/scenarios to understand would be valuable. I want to know what is possible to do without the OS running and the PC with running (therefore electricity is available)

I run Debian 10/Gnome on a Lenovo Y2P, so far without problem. In particular uname -a yields:

Linux deepthought 4.19.0-13-amd64 #1 SMP Debian 4.19.160-2 (2020-11-28) x86_64 GNU/Linux

Since I once ran sudo halt on 4.19.0-11-amd64, synclient -l yields: > Couldn't find synaptics properties. No synaptics driver loaded? I.e. the touchpad works, but less sensitive, no 2-FingerScroll, no click-drag, and the Mouse & Touchpad settings menu is reduced to a basic form. On the previous version, 4.19.0-10-amd64 the touchpad still works completely normal. Here is, what I tried so far: 1. I have xserver-xorg-input-libinput and xserver-xorg-input-synaptics installed (and re-installed, to no avail). 2. As in this StackExchange answer, xinput list yields: > ↳ PS/2 Synaptics TouchPad id=13 [slave pointer (2)] but copying the synaptics config file, as suggested:

cp /usr/share/X11/xorg.conf.d/70-synaptics.conf /etc/X11/xorg.conf.d/70-synaptics.conf

and rebooting did not solve the problem. The content of 70-synaptics.conf is:

# Example xorg.conf.d snippet that assigns the touchpad driver
# to all touchpads. See xorg.conf.d(5) for more information on
# InputClass.
# DO NOT EDIT THIS FILE, your distribution will likely overwrite
# it when updating. Copy (and rename) this file into
# /etc/X11/xorg.conf.d first.
# Additional options may be added in the form of
#   Option "OptionName" "value"
#
Section "InputClass"
        Identifier "touchpad catchall"
        Driver "synaptics"
        MatchIsTouchpad "on"
# This option is recommend on all Linux systems using evdev, but cannot be
# enabled by default. See the following link for details:
# http://who-t.blogspot.com/2010/11/how-to-ignore-configuration-errors.html 
#       MatchDevicePath "/dev/input/event*"
EndSection

Section "InputClass"
        Identifier "touchpad ignore duplicates"
        MatchIsTouchpad "on"
        MatchOS "Linux"
        MatchDevicePath "/dev/input/mouse*"
        Option "Ignore" "on"
EndSection

# This option enables the bottom right corner to be a right button on clickpads
# and the right and middle top areas to be right / middle buttons on clickpads
# with a top button area.
# This option is only interpreted by clickpads.
Section "InputClass"
        Identifier "Default clickpad buttons"
        MatchDriver "synaptics"
        Option "SoftButtonAreas" "50% 0 82% 0 0 0 0 0"
        Option "SecondarySoftButtonAreas" "58% 0 0 15% 42% 58% 0 15%"
EndSection

# This option disables software buttons on Apple touchpads.
# This option is only interpreted by clickpads.
Section "InputClass"
        Identifier "Disable clickpad buttons on Apple touchpads"
        MatchProduct "Apple|bcm5974"
        MatchDriver "synaptics"
        Option "SoftButtonAreas" "0 0 0 0 0 0 0 0"
EndSection

3. Re-adding the module to the kernel did not help but tells me this: insmod /lib/modules/4.19.0-13-amd64/kernel/drivers/input/mouse/psmouse.ko proto=imps 4. Following this reddit, i checked dmesg like so:

$ sudo dmesg | grep -i PS/2
[    1.799257] i8042: PNP: PS/2 Controller [PNP0303:PS2K,PNP0f13:PS2M] at 0x60,0x64 irq 1,12
[    1.812958] mousedev: PS/2 mouse device common for all mice
[    2.218457] input: PS/2 Synaptics TouchPad as /devices/platform/i8042/serio1/input/input5
[  246.027504] input: PS/2 Synaptics TouchPad as /devices/platform/i8042/serio1/input/input81

However, my xorg log contains nothing about Synaptics:

[   189.259] 
X.Org X Server 1.20.4
X Protocol Version 11, Revision 0
[   189.259] Build Operating System: Linux 4.9.0-8-amd64 x86_64 Debian
[   189.259] Current Operating System: Linux deepthought 4.19.0-10-amd64 #1 SMP Debian 4.19.132-1 (2020-07-24) x86_64
[   189.259] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-4.19.0-10-amd64 root=UUID=48c75b27-4eb3-426f-9a8b-80bac1fc66d5 ro quiet
[   189.259] Build Date: 05 March 2019  08:11:12PM
[   189.259] xorg-server 2:1.20.4-1 (https://www.debian.org/support)  
[   189.259] Current version of pixman: 0.36.0
[   189.259]    Before reporting problems, check http://wiki.x.org 
        to make sure that you have the latest version.
[   189.259] Markers: (--) probed, (**) from config file, (==) default setting,
        (++) from command line, (!!) notice, (II) informational,
        (WW) warning, (EE) error, (NI) not implemented, (??) unknown.
[   189.260] (==) Log file: "/var/log/Xorg.0.log", Time: Thu Aug  6 14:41:07 2020
[   189.260] (==) Using config directory: "/etc/X11/xorg.conf.d"
[   189.260] (==) Using system config directory "/usr/share/X11/xorg.conf.d"
[   189.261] Parse error on line 3 of section Device in file /etc/X11/xorg.conf.d/20-displaylink.conf
        "MatchDriver" is not a valid keyword in this section.
[   189.262] (EE) Problem parsing the config file
[   189.262] (EE) Error parsing the config file
[   189.262] (EE) 
Fatal server error:
[   189.262] (EE) no screens found(EE) 
[   189.262] (EE) 
Please consult the The X.Org Foundation support 
         at http://wiki.x.org 
 for help. 
[   189.262] (EE) Please also check the log file at "/var/log/Xorg.0.log" for additional information.
[   189.262] (EE) 
[   189.262] (EE) Server terminated with error (1). Closing log file.

The error in here stems from another halted project - it has not influenced the synaptics driver in the past. But I don't see anything about the latter. (side question: i removed the file 20-displaylink.conf a while ago, i.e. this file doesn't exist anymore. when/how does this log get updated?) 5. As I expected, adding the module automatically at start up, as suggested here did not change anything. 6. This link tells me, that Gnome 3.20 no longer supports synaptic drivers, but switched to libinput. I have 3.30.2., so while the behavior would make sense, I have the same Gnome version on the Kernel version 4.19.0-10-amd64, and it works just fine. Anyhow, this wiki entry should then tell me how to switch to libinput - but i seem to be too stupehd for that, i.e. I don't get what I need to do. Now, slowly desperation kicks in, as I am not (yet) familiar enough with Linux, to cook up my own solution. Hence, any help is greatly appreciated. Also: how could halt mess this up? Is there some danger to it, I should know about? Thank you big time!

I'm having issues trying to understand why my system randomly halts or reboots. Here are the specs of my system, retrieved using neofetch:

.-/+oossssoo+/-.
        :+ssssssssssssssssss+:           aeryan@aeryan-PC 
      -+ssssssssssssssssssyyssss+-         ---------------- 
    .ossssssssssssssssssdMMMNysssso.       OS: Ubuntu 20.04.1 LTS x86_64 
   /ssssssssssshdmmNNmmyNMMMMhssssss/      Kernel: 5.4.0-58-generic 
  +ssssssssshmydMMMMMMMNddddyssssssss+     Uptime: 44 mins 
 /sssssssshNMMMyhhyyyyhmNMMMNhssssssss/    Packages: 2422 (dpkg), 6 (snap) 
.ssssssssdMMMNhsssssssssshNMMMdssssssss.   Shell: bash 5.0.17 
+sssshhhyNMMNyssssssssssssyNMMMysssssss+   Resolution: 1920x1080, 1920x1080 
ossyNMMMNyMMhsssssssssssssshmmmhssssssso   DE: Plasma 
ossyNMMMNyMMhsssssssssssssshmmmhssssssso   WM: KWin 
+sssshhhyNMMNyssssssssssssyNMMMysssssss+   WM Theme: breeze 
.ssssssssdMMMNhsssssssssshNMMMdssssssss.   Theme: Breeze Dark [Plasma], Breeze [GTK2/3] 
 /sssssssshNMMMyhhyyyyhdNMMMNhssssssss/    Icons: breeze-dark [Plasma], breeze-dark [GTK2/3] 
  +sssssssssdmydMMMMMMMMddddyssssssss+     Terminal: konsole 
   /ssssssssssshdmNNNNmyNMMMMhssssss/      Terminal Font: Ubuntu Mono 13.2 
    .ossssssssssssssssssdMMMNysssso.       CPU: AMD Ryzen 5 3600X (12) @ 3.800GHz 
      -+sssssssssssssssssyyyssss+-         GPU: NVIDIA GeForce RTX 2060 Rev. A 
        :+ssssssssssssssssss+:           Memory: 16448MiB / 32105MiB

I'm using this machine to run ML algorithms using TensorFlow. However, I've been monitoring CPU and GPU temperatures and it doesn't seem the system halts because of reaching a critical temperature. One thing to take into account is that my system is not upgraded to the last version (I have used the *hold* command to prevent my kernel from upgrading), since I had incompatibilities between the newer kernel versions and my code version. I have taken a look at *syslog* for the time of the last unexpected reboot, and this is what I have found:

Jul  7 12:41:43 aeryan-PC systemd: unattended-upgrades.service: Succeeded.
Jul  7 12:41:43 aeryan-PC sddm: Authentication error: "Process crashed"
Jul  7 12:41:43 aeryan-PC sddm: Auth: sddm-helper crashed (exit code 15)
Jul  7 12:41:43 aeryan-PC sddm: Authentication error: "Process crashed"
Jul  7 12:41:43 aeryan-PC sddm: Auth: sddm-helper exited with 15
Jul  7 12:41:43 aeryan-PC sddm: Socket server stopping...
Jul  7 12:41:43 aeryan-PC sddm: Socket server stopped.
Jul  7 12:41:43 aeryan-PC sddm: Display server stopping...
Jul  7 12:41:43 aeryan-PC systemd: Stopping Session 3 of user aeryan.
Jul  7 12:41:43 aeryan-PC systemd: Removed slice system-getty.slice.
Jul  7 12:41:43 aeryan-PC systemd: Removed slice system-modprobe.slice.
Jul  7 12:41:43 aeryan-PC systemd: Stopped target Graphical Interface.
Jul  7 12:41:43 aeryan-PC systemd: Stopped target Multi-User System.
Jul  7 12:41:43 aeryan-PC systemd: Stopped target Login Prompts.
Jul  7 12:41:43 aeryan-PC systemd: Stopped target Sound Card.
Jul  7 12:41:43 aeryan-PC systemd: Stopped target Timers.
Jul  7 12:41:43 aeryan-PC systemd: apt-daily-upgrade.timer: Succeeded.
Jul  7 12:41:43 aeryan-PC systemd: Stopped Daily apt upgrade and clean activities.
Jul  7 12:41:43 aeryan-PC systemd: apt-daily.timer: Succeeded.
Jul  7 12:41:43 aeryan-PC systemd: Stopped Daily apt download activities.
Jul  7 12:41:43 aeryan-PC systemd: e2scrub_all.timer: Succeeded.
Jul  7 12:41:43 aeryan-PC systemd: Stopped Periodic ext4 Online Metadata Check for All Filesystems.
Jul  7 12:41:43 aeryan-PC systemd: fstrim.timer: Succeeded.
Jul  7 12:41:43 aeryan-PC systemd: Stopped Discard unused blocks once a week.
Jul  7 12:41:43 aeryan-PC systemd: fwupd-refresh.timer: Succeeded.
Jul  7 12:41:43 aeryan-PC systemd: Stopped Refresh fwupd metadata regularly.
Jul  7 12:41:43 aeryan-PC systemd: logrotate.timer: Succeeded.
Jul  7 12:41:43 aeryan-PC systemd: Stopped Daily rotation of log files.
Jul  7 12:41:43 aeryan-PC systemd: man-db.timer: Succeeded.
Jul  7 12:41:43 aeryan-PC systemd: Stopped Daily man-db regeneration.
Jul  7 12:41:43 aeryan-PC systemd: motd-news.timer: Succeeded.
Jul  7 12:41:43 aeryan-PC systemd: Stopped Message of the Day.
Jul  7 12:41:43 aeryan-PC systemd: systemd-tmpfiles-clean.timer: Succeeded.
Jul  7 12:41:43 aeryan-PC systemd: Stopped Daily Cleanup of Temporary Directories.
Jul  7 12:41:43 aeryan-PC systemd: systemd-rfkill.socket: Succeeded.
Jul  7 12:41:43 aeryan-PC systemd: Closed Load/Save RF Kill Switch Status /dev/rfkill Watch.
Jul  7 12:41:43 aeryan-PC systemd: Unmounting /home/aeryan/Windows/D:...
Jul  7 12:41:43 aeryan-PC systemd: Unmounting /home/aeryan/Windows/F:...
Jul  7 12:41:43 aeryan-PC systemd: Stopping Modem Manager...
Jul  7 12:41:43 aeryan-PC ModemManager:   Caught signal, shutting down...
Jul  7 12:41:43 aeryan-PC systemd: Stopping Accounts Service...
Jul  7 12:41:43 aeryan-PC anacron: Received SIGUSR1
Jul  7 12:41:43 aeryan-PC systemd: Stopping ACPI event daemon...
Jul  7 12:41:43 aeryan-PC anacron: Exited
Jul  7 12:41:43 aeryan-PC systemd: Stopping Save/Restore Sound Card State...
Jul  7 12:41:43 aeryan-PC ModemManager:   ModemManager is shut down
Jul  7 12:41:43 aeryan-PC systemd: Stopping Run anacron jobs...
Jul  7 12:41:43 aeryan-PC systemd: Stopping LSB: automatic crash report generation...
Jul  7 12:41:43 aeryan-PC systemd: Stopping Deferred execution scheduler...
Jul  7 12:41:43 aeryan-PC ntfs-3g: Unmounting /dev/sdc1 (External Drive)
Jul  7 12:41:43 aeryan-PC systemd: Stopping Regular background program processing daemon...
Jul  7 12:41:43 aeryan-PC ntfs-3g: Permissions cache : 1 writes, 3 reads, 100.0% hits
Jul  7 12:41:43 aeryan-PC systemd: Stopping Make remote CUPS printers available locally...
Jul  7 12:41:43 aeryan-PC nvidia-persistenced: Received signal 15
Jul  7 12:41:43 aeryan-PC NetworkManager:   [1625654503.0645] modem-manager: ModemManager no longer available
Jul  7 12:41:43 aeryan-PC nvidia-persistenced: Socket closed.
Jul  7 12:41:43 aeryan-PC systemd: Stopping LSB: Record successful boot for GRUB...
Jul  7 12:41:43 aeryan-PC nvidia-persistenced: PID file unlocked.
Jul  7 12:41:43 aeryan-PC snapd: main.go:155: Exiting on terminated signal.
Jul  7 12:41:43 aeryan-PC systemd: home-aeryan-Windows-F:.mount: Succeeded.
Jul  7 12:41:43 aeryan-PC nvidia-persistenced: PID file closed.
Jul  7 12:41:43 aeryan-PC systemd: Stopping irqbalance daemon...
Jul  7 12:41:43 aeryan-PC nvidia-persistenced: The daemon no longer has permission to remove its runtime data directory /var/run/nvidia-persistenced
Jul  7 12:41:43 aeryan-PC systemd: Stopping Tool to automatically collect and submit kernel crash signatures...
Jul  7 12:41:43 aeryan-PC nvidia-persistenced: Shutdown (1123)
Jul  7 12:41:43 aeryan-PC systemd: Stopping Dispatcher daemon for systemd-networkd...
Jul  7 12:41:43 aeryan-PC Tor: Interrupt: exiting cleanly.
Jul  7 12:41:43 aeryan-PC systemd: Stopping NVIDIA Persistence Daemon...
Jul  7 12:41:43 aeryan-PC systemd: Stopping PackageKit Daemon...
Jul  7 12:41:43 aeryan-PC systemd: Stopping System Logging Service...
Jul  7 12:41:43 aeryan-PC systemd: Stopping RealtimeKit Scheduling Policy Service...
Jul  7 12:41:43 aeryan-PC systemd: Stopping Simple Desktop Display Manager...
Jul  7 12:41:43 aeryan-PC systemd: snapd.seeded.service: Succeeded.
Jul  7 12:41:43 aeryan-PC systemd: Stopped Wait until snapd is fully seeded.
Jul  7 12:41:43 aeryan-PC systemd: Stopping Snap Daemon...
Jul  7 12:41:43 aeryan-PC systemd: Condition check resulted in Ubuntu core (all-snaps) system shutdown helper setup service being skipped.
Jul  7 12:41:43 aeryan-PC systemd: tor.service: Succeeded.
Jul  7 12:41:43 aeryan-PC systemd: Stopped Anonymizing overlay network for TCP (multi-instance-master).

I have difficulties in understanding all of the logs but, from what I've seen, it seems like the process *sddm* crashes and then *systemd* reboots my system. In other cases, my computer does not reboot but rather shutdowns incompletely. By this I mean my screen has no signal but my computer is still on (the lights, CPU, etc. are on) as if it had not completed the shutdown. Thus, I don't know if *sddm* crashing is responsible for all the reboots, shutdowns or none of them. Another possible cause could be small blackouts, but in that case I don't know if my computer would completely shutdown. Edit: As Daniel Kelley suggested I'm also uploading the contents of the /var/log/kern.log and /var/log/dmesg files: **/var/log/kern.log** (around the time when the crash happened)

Jul  7 12:38:48 aeryan-PC kernel: [   14.574092] Generic FE-GE Realtek PHY r8169-400:00: attached PHY driver [Generic FE-GE Realtek PHY] (mii_bus:phy_addr=r8169-400:00, irq=IGNORE)
Jul  7 12:38:48 aeryan-PC kernel: [   14.689224] r8169 0000:04:00.0 enp4s0: Link is Down
Jul  7 12:38:49 aeryan-PC kernel: [   15.505398] resource sanity check: requesting [mem 0x000c0000-0x000fffff], which spans more than PCI Bus 0000:00 [mem 0x000c0000-0x000dffff window]
Jul  7 12:38:49 aeryan-PC kernel: [   15.505502] caller os_map_kernel_space.part.0+0x77/0xa0 [nvidia] mapping multiple BARs
Jul  7 12:38:52 aeryan-PC kernel: [   18.324043] r8169 0000:04:00.0 enp4s0: Link is Up - 1Gbps/Full - flow control rx/tx
Jul  7 12:38:52 aeryan-PC kernel: [   18.324053] IPv6: ADDRCONF(NETDEV_CHANGE): enp4s0: link becomes ready
Jul  7 12:39:18 aeryan-PC kernel: [   43.913570] vboxdrv: Found 12 processor cores
Jul  7 12:39:18 aeryan-PC kernel: [   43.936179] vboxdrv: TSC mode is Invariant, tentative frequency 3792870341 Hz
Jul  7 12:39:18 aeryan-PC kernel: [   43.936180] vboxdrv: Successfully loaded version 6.1.16_Ubuntu (interface 0x00300000)
Jul  7 12:39:18 aeryan-PC kernel: [   43.940829] VBoxNetFlt: Successfully started.
Jul  7 12:39:18 aeryan-PC kernel: [   43.943962] VBoxNetAdp: Successfully started.
Jul  7 12:39:31 aeryan-PC kernel: [   57.296443] EXT4-fs (sdb5): recovery complete
Jul  7 12:39:31 aeryan-PC kernel: [   57.296446] EXT4-fs (sdb5): mounted filesystem with ordered data mode. Opts: (null)
Jul  7 12:39:31 aeryan-PC kernel: [   57.296452] ext4 filesystem being mounted at /media/aeryan/141f23da-6fba-4ad7-9f78-b5c4402a237f supports timestamps until 2038 (0x7fffffff)
Jul  7 12:39:32 aeryan-PC kernel: [   58.116033] snd_hda_codec_hdmi hdaudioC0D0: HDMI: invalid ELD data byte 9
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] Linux version 5.4.0-58-generic (buildd@lcy01-amd64-004) (gcc version 9.3.0 (Ubuntu 9.3.0-17ubuntu1~20.04)) #64-Ubuntu SMP Wed Dec 9 08:16:25 UTC 2020 (Ubuntu 5.4.0-58.64-generic 5.4.73)
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-5.4.0-58-generic root=UUID=3bd10f61-1b04-4b2b-a5b1-f8a3534b852a ro quiet splash vt.handoff=7
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] KERNEL supported cpus:
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000]   Intel GenuineIntel
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000]   AMD AuthenticAMD
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000]   Hygon HygonGenuine
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000]   Centaur CentaurHauls
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000]   zhaoxin   Shanghai  
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] x86/fpu: Supporting XSAVE feature 0x001: 'x87 floating point registers'
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] x86/fpu: Supporting XSAVE feature 0x002: 'SSE registers'
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] x86/fpu: Supporting XSAVE feature 0x004: 'AVX registers'
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] x86/fpu: xstate_offset:  576, xstate_sizes:  256
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] x86/fpu: Enabled xstate features 0x7, context size is 832 bytes, using 'compacted' format.
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-provided physical RAM map:
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009d3ff] usable
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x000000000009d400-0x000000000009ffff] reserved
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x00000000000e0000-0x00000000000fffff] reserved
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x0000000000100000-0x0000000009e0ffff] usable
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x0000000009e10000-0x0000000009ffffff] reserved
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x000000000a000000-0x000000000a1fffff] usable
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x000000000a200000-0x000000000a20bfff] ACPI NVS
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x000000000a20c000-0x000000000affffff] usable
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x000000000b000000-0x000000000b01ffff] reserved
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x000000000b020000-0x00000000d0f40fff] usable
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x00000000d0f41000-0x00000000d0f60fff] ACPI data
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x00000000d0f61000-0x00000000d9e07fff] usable
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x00000000d9e08000-0x00000000d9f4afff] reserved
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x00000000d9f4b000-0x00000000d9f5afff] ACPI data
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x00000000d9f5b000-0x00000000da065fff] usable
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x00000000da066000-0x00000000da424fff] ACPI NVS
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x00000000da425000-0x00000000db778fff] reserved
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x00000000db779000-0x00000000ddffffff] usable
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x00000000de000000-0x00000000dfffffff] reserved
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x00000000f8000000-0x00000000fbffffff] reserved
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x00000000fd000000-0x00000000fd0fffff] reserved
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x00000000fd500000-0x00000000fd5fffff] reserved
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x00000000fea00000-0x00000000fea0ffff] reserved
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x00000000feb80000-0x00000000fec01fff] reserved
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x00000000fec10000-0x00000000fec10fff] reserved
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x00000000fec30000-0x00000000fec30fff] reserved
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x00000000fed00000-0x00000000fed00fff] reserved
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x00000000fed40000-0x00000000fed44fff] reserved
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x00000000fed80000-0x00000000fed8ffff] reserved
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x00000000fedc2000-0x00000000fedcffff] reserved
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x00000000fedd4000-0x00000000fedd5fff] reserved
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x00000000fee00000-0x00000000feefffff] reserved
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x00000000ff000000-0x00000000ffffffff] reserved
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] BIOS-e820: [mem 0x0000000100000000-0x000000081f37ffff] usable
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] NX (Execute Disable) protection: active
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] SMBIOS 3.1.1 present.
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] DMI: System manufacturer System Product Name/TUF B450-PLUS GAMING, BIOS 2008 12/06/2019
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] tsc: Fast TSC calibration using PIT
Jul  7 12:42:24 aeryan-PC kernel: [    0.000000] tsc: Detected 3792.911 MHz processor

**/var/log/dmesg** (first lines of the file)

[mié jul  7 12:54:58 2021] Linux version 5.4.0-58-generic (buildd@lcy01-amd64-004) (gcc version 9.3.0 (Ubuntu 9.3.0-17ubuntu1~20.04)) #64-Ubuntu SMP Wed Dec 9 08:16:25 UTC 2020 (Ubuntu 5.4.0-58.64-generic 5.4.73)
[mié jul  7 12:54:58 2021] Command line: BOOT_IMAGE=/boot/vmlinuz-5.4.0-58-generic root=UUID=3bd10f61-1b04-4b2b-a5b1-f8a3534b852a ro quiet splash vt.handoff=7
[mié jul  7 12:54:58 2021] KERNEL supported cpus:
[mié jul  7 12:54:58 2021]   Intel GenuineIntel
[mié jul  7 12:54:58 2021]   AMD AuthenticAMD
[mié jul  7 12:54:58 2021]   Hygon HygonGenuine
[mié jul  7 12:54:58 2021]   Centaur CentaurHauls
[mié jul  7 12:54:58 2021]   zhaoxin   Shanghai  
[mié jul  7 12:54:58 2021] x86/fpu: Supporting XSAVE feature 0x001: 'x87 floating point registers'
[mié jul  7 12:54:58 2021] x86/fpu: Supporting XSAVE feature 0x002: 'SSE registers'
[mié jul  7 12:54:58 2021] x86/fpu: Supporting XSAVE feature 0x004: 'AVX registers'
[mié jul  7 12:54:58 2021] x86/fpu: xstate_offset:  576, xstate_sizes:  256
[mié jul  7 12:54:58 2021] x86/fpu: Enabled xstate features 0x7, context size is 832 bytes, using 'compacted' format.
[mié jul  7 12:54:58 2021] BIOS-provided physical RAM map:
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x0000000000000000-0x000000000009d3ff] usable
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x000000000009d400-0x000000000009ffff] reserved
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x00000000000e0000-0x00000000000fffff] reserved
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x0000000000100000-0x0000000009e0ffff] usable
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x0000000009e10000-0x0000000009ffffff] reserved
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x000000000a000000-0x000000000a1fffff] usable
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x000000000a200000-0x000000000a20bfff] ACPI NVS
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x000000000a20c000-0x000000000affffff] usable
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x000000000b000000-0x000000000b01ffff] reserved
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x000000000b020000-0x00000000d0f40fff] usable
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x00000000d0f41000-0x00000000d0f60fff] ACPI data
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x00000000d0f61000-0x00000000d9e07fff] usable
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x00000000d9e08000-0x00000000d9f4afff] reserved
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x00000000d9f4b000-0x00000000d9f5afff] ACPI data
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x00000000d9f5b000-0x00000000da065fff] usable
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x00000000da066000-0x00000000da424fff] ACPI NVS
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x00000000da425000-0x00000000db778fff] reserved
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x00000000db779000-0x00000000ddffffff] usable
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x00000000de000000-0x00000000dfffffff] reserved
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x00000000f8000000-0x00000000fbffffff] reserved
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x00000000fd000000-0x00000000fd0fffff] reserved
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x00000000fd500000-0x00000000fd5fffff] reserved
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x00000000fea00000-0x00000000fea0ffff] reserved
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x00000000feb80000-0x00000000fec01fff] reserved
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x00000000fec10000-0x00000000fec10fff] reserved
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x00000000fec30000-0x00000000fec30fff] reserved
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x00000000fed00000-0x00000000fed00fff] reserved
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x00000000fed40000-0x00000000fed44fff] reserved
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x00000000fed80000-0x00000000fed8ffff] reserved
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x00000000fedc2000-0x00000000fedcffff] reserved
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x00000000fedd4000-0x00000000fedd5fff] reserved
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x00000000fee00000-0x00000000feefffff] reserved
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x00000000ff000000-0x00000000ffffffff] reserved
[mié jul  7 12:54:58 2021] BIOS-e820: [mem 0x0000000100000000-0x000000081f37ffff] usable
[mié jul  7 12:54:58 2021] NX (Execute Disable) protection: active
[mié jul  7 12:54:58 2021] SMBIOS 3.1.1 present.

I pasted a long list of commands into Bash, and in the middle of execution, I decided I wanted it to stop. Ctrl+Z and Ctrl+C did nothing. It just continues executing line after line. In the end, the commands required a service to be running, so I stopped that instead using another SSH instance, and the commands errored out one after the other. If I hadn't been able to stop a service to do that, how would I stop the list from continuing to execute?

I used the command poweroff and unexpectedly the system went off. I didn't used sudo therefore I didn't expect computer to be turned off. Why it was possible for me to use this command without root privilege?

I am using a bash script with the shutdown command to halt my system. I know that shutdown can print a message as an argument. Here's my current command: shutdown -h now "Shutdown complete. You may now unplug the power." However, this prints my message *before* the shutdown command does its thing, and so I see a ton of other messages afterwards, such as "INIT: Sending processes the TERM signal" and "Unmounting local filesystems..." I want to print a final message at the end of the halt, so that the user knows when it is safe to unplug the power. How can I do this? (I am on an embedded system running Petalinux 2019.1.)

I need to ability to halt an aws EC2 server as user. I found https://www.cyberciti.biz/tips/howto-linux-allow-users-to-shutdown-server.html but due to the fact that I need this feature on an aws EC2 instance, I don't have a static hostname, so I tried: ubuntu ALL=(ALL:ALL) ALL=/sbin/halt /sbin/reboot but that got me: >>> /etc/sudoers: syntax error near line 21 <<< What now? Options are: (e)dit sudoers file again e(x)it without saving changes to sudoers file (Q)uit and save changes to sudoers file (DANGER!) how can I solve this correctly?

**Summary:** How do I make the following cheat-code permanent on knoppix 8.6.1 on usb stick, because filesystem type is iso9660 (read-only) and won't let me edit /mnt-system/boot/isolinux/isolinux.cfg. **Cheat code entered at boot prompt:** knoppix xmodule=vesa **Full Details:** I've just put knoppix 8.6.1 on a usb stick (persistence was there by default). But X Window won't display unless I enter the cheat-code "knoppix xmodule=vesa" at the initial boot prompt. Incidentally, when using Knoppix 7.7.1 on a usb stick, on the EXACT SAME laptop (Acer Aspire 5755G), I don't need the cheat-code. I'd like to **not have to type the cheat-code in every time** I boot the 8.6.1, and believe that I can achieve that by adding "xmodule=vesa" as a kernel parameter on an "APPEND" line in /boot/isolinux/isolinux.cfg. I can get to that file using the path /mnt-system/boot/isolinux/isolinux.cfg. **But it won't let me write** to that file because /mnt-system is mounted read only. When I try to remount /mnt-system as read-write, it says "write-protected." /UNIONFS **is** mounted as read-write, but the path /UNIONFS/boot/isolinux/ does not exist. I understand that because partition 1 (the main Knoppix system) is filesystem type iso9660*, that it is by definition read-only. (*On which I believe /boot/isolinux/isolinux.cfg sits). **Main Question:** So could you tell me please, what method I need to use to make my cheat-code permanent? **Reason for Using 8.6.1:** I'm trying out 8.6.1 because it has a newer kernel than 7.7.1, and I've read that a newer kernel might fix my problem of downloads halting when the lid is closed. I've already tried many lid disabling methods, but none of them prevent the downloading from halting.

I want to have the message system halted after command shutdown -H now, but my new PC after this command power-off the machine. With my old PC that command worked fine. But my new PC is powered down after the command shutdown -H now instead of halting with message system halted on screen. What happened? How to return normal behaviour of the shutdown -H now command? OS version is Debian 8.5. Same version of OS is using on both machines, but reactions on shutdown -H now command are different. Could it be settings in BIOS? Could it be a hardware problem?

I have sometimes internet disconnection from my wifi connection to my home wifi modem. I have one Linux LMDE OS into my Lenovo IdeaPad 310 laptop, so in regular times I have this: so@notebook:~$ uname -a Linux notebook 4.9.0-9-amd64 #1 SMP Debian 4.9.168-1 (2019-04-12) x86_64 GNU/Linux   so@notebook:~$ ifconfig            wlp2s0: flags=4163  mtu 1500        inet 192.168.1.105  netmask 255.255.255.0  broadcast 192.168.1.255        inet6 fe80::59dc:548c:4eb2:a3e5  prefixlen 64  scopeid 0x20        ether c8:3d:d4:3c:23:63  txqueuelen 1000  (Ethernet)        RX packets 50050  bytes 46065327 (43.9 MiB)        RX errors 0  dropped 0  overruns 0  frame 0        TX packets 40256  bytes 6564953 (6.2 MiB)        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0 but when my wifi internet disconnected I have this: so@notebook:~$ ifconfig            wlp2s0: flags=4163  mtu 1500        inet6 fe80::59dc:548c:4eb2:a3e5  prefixlen 64  scopeid 0x20        ether c8:3d:d4:3c:23:63  txqueuelen 1000  (Ethernet)        RX packets 50203  bytes 46102351 (43.9 MiB)        RX errors 0  dropped 0  overruns 0  frame 0        TX packets 40387  bytes 6581340 (6.2 MiB)        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0 and my wifi setting could be seen here: **Update:** Based on comments I have: so@notebook:~$ lspci -knn | grep Net -A3 02:00.0 Network controller : Realtek Semiconductor Co., Ltd. RTL8821AE 802.11ac PCIe Wireless Network Adapter [10ec:8821] Subsystem: Lenovo RTL8821AE 802.11ac PCIe Wireless Network Adapter [17aa:a814] Kernel driver in use: rtl8821ae Kernel modules: rtl8821ae 03:00.0 3D controller : NVIDIA Corporation GM108M [GeForce 920MX] [10de:134f] (rev a2) So why this happened?

**IMPORTANT:** **I am able to restore halt old behavior if I do:** apt install sysvinit-core **Plus:** Old **Red Hat** based versions are able to power off with halt too. I am trying to understand why in Debian 9 you should not use halt to turn off your computer anymore. That behavior are removed from systemd. I am a bit scary, but I think there must be a good logical reason. Are other unixes or unix-like with this same behavior or are Linux turning into something different? Now if you want to turn off the machine after the system shutdown you should use poweroff instead of halt... Somebody know how this command are interpreted in other Unix-Like? That is not a duplicated, because, debian 7 can power off with halt for example.