GRUB hidden menu change FAQ  

The Discoverable Partitions Specification

There is one very important reason for enabling job control to be useful inside scripts: the side-effect it has of placing background processes in their own process groups. This makes it much, much easier to send signels to them and their children with one simple command: kill -<signal> -$pgid. All other ways of dealing with signaling entire trees of processes either involve elaborate (sometimes even recursive) functions, which are often bugnests, or risk killing the parent in the process (no pun intended).

Arteck HB030 Keyboard and Normal Escape

The alternative for curl is a credential file: A .netrc file can be used to store credentials for servers you need to connect to.And for mysql, you can create option files: a .my.cnf or an obfuscated .mylogin.cnf will be read on startup and can contain your passwords.

Linux keyring offers several scopes for storing keys safely in memory that will never be swapped to disk. A process or even a single thread can have its own keyring, or you can have a keyring that is inherited across all processes in a user’s session. To manage the keyrings and keys, use the keyctl command or keyctl system calls.

Docker container can call out to a secrets manager for its secrets. But, a secrets manager is an extra dependency. Often you need to run a secrets manager server and hit an API. And even with a secrets manager, you may still need Bash to shuttle the secret into your target application.

Using environment variables for secrets is very convenient. And we don’t recommend it because it’s so easy to leak things

As the sanitized example shows, a pipeline is generally an excellent way to pass secrets around, if the program you’re using will accept a secret via STDIN.

A few notes about storing and retrieving file secrets

As it stands, sudo -i is the most practical, clean way to gain a root environment. On the other hand, those using sudo -s will find they can gain a root shell without the ability to touch the root environment, something that has added security benefits.

Much like sudo su, the -i flag allows a user to get a root environment without having to know the root account password. sudo -i is also very similar to using sudo su in that it’ll read all of the environmental files (.profile, etc.) and set the environment inside the shell with it.

This means that unlike a command like sudo -i or sudo su, the system will not read any environmental files. This means that when a user tells the shell to run sudo -s, it gains root but will not change the user or the user environment. Your home will not be the root home, etc. This command is best used when the user doesn’t want to touch root at all and just wants a root shell for easy command execution.

Though there isn’t very much difference from “su,” sudo su is still a very useful command for one important reason: When a user is running “su” to gain root access on a system, they must know the root password. The way root is given with sudo su is by requesting the current user’s password. This makes it possible to gain root without the root password which increases security.

“su” is best used when a user wants direct access to the root account on the system. It doesn’t go through sudo or anything like that. Instead, the root user’s password has to be known and used to log in with.

On RHEL-based operating systems (like CentOS and Fedora), use yum

On Debian-based operating systems (like Ubuntu), use apt-get

Disclaimer If this tool works, great! However, no guarantees are made that it won't hasten the heat death of the universe through the spontaneous combustion of your CPU.

What is the equivalent of unbuffer program on Windows?

If there are some pipe between these commands, you need to flush stdout. for example: script -q /dev/null commands... | ruby -ne 'print "....\n";STDOUT.flush'

By default, fork(2) places a newly created child process in the same process group as its parent, so that e.g. a ^C from the keyboard will affect both parent and child.

But the shell, as part of its session leader duties, creates a new process group every time it launches a pipeline.

Job control is what happens when you press ^Z to suspend a program, or when you start a program in the background using &

A job is the same as a process group.

Windows Subsystem for Linux, also known as WSL, is a compatibility layer for running Linux binary executables natively on Windows 10 using a Linux image

i found that for the osx host "gonzo" , the vanished files (not the warning message itself) appear in stdout - for linux hosts they _both_ appear in stderr , but nothing in stdout (rsync.err.#num is stderr, rsync.log is stdout)

Proton is a new tool released by Valve Software that has been integrated with Steam Play to make playing Windows games on Linux as simple as hitting the Play button within Steam. Underneath the hood, Proton comprises other popular tools like Wine and DXVK among others that a gamer would otherwise have to install and maintain themselves. This greatly eases the burden for users to switch to Linux without having to learn the underlying systems or losing access to a large part of their library of games. Proton is still in its infancy so support is inconsistent, but regularly improving.

I've been made aware of a "Compatibility tool to run DOS games on Steam through native Linux DOSBox" called "steam-dos". It can be found on https://www.github.com/dreamer/steam-dos . I pulled this tool from git and using it as the the steam play compatibility tool Megarace 2 runs without issue. Saving both settings and games works again! There is no keyboard support for controlling the vehicle in game but both mouse and joystick/gamepad work. To get around a missing launcher.exe error I copied "MegaRace 2.exe" to the same folder as the original and renamed the copy to "Launcher.exe". Linux users: in your MegaRace 2 folder (steamapps/common/MegaRace 2/) create a symbolic link to start.sh named Launcher.exe. This allows the game to launch through Steam. This also allows you to put time on the game through Steam, hitting that coveted 5 minute mark that makes creating a review possible. With that out of the way, the game itself is a nice touch of nostalgia but the port is absolutely terrible. I don't remember it being quite this difficult to install off the 2 CDs. The game won't launch at all without tweaking. Can't save the config settings. Can't save the game at all in fact. While I really like MegaRace 2, you unlock tracks by completing the previous ones. Since the game can't be saved, I end up running The Foundry track over and over until I'm sick of it.So I'm torn. I love the game but I hate the completely broken port. For $3 and a local install of DOSBOX it can be made to work so I will recommend it anyway.

The reason we've avoided registering "Cinnamon" as a desktop name is that it opens up issues with many upstream apps that currently OnlyShowIn=Gnome or Gnome;Unity or just Unity. The relationship Mint has with Gnome and Ubuntu isn't genial enough that we could get them to add Cinnamon to their desktop files, so we would have to distribute and maintain separate duplicate .desktop files just for Cinnamon for these upstream packages.

Also manually adding [Default Applications] x-scheme-handler/zoommtg=ZoomLauncher.desktop to either $HOME/.config/mimeapps.list or $HOME/.local/share/applications/mimeapps.list does not lead to xdg-open via exo-open recognizing the zoommtg protocol.

xdg-email

There's a command that knows about your default browser: xdg-open http://google.com This will also work for every other type of URI (Uniform Resource Identifier), like images - which will automatically open with eog, openoffice documents, and so on, and also on filesystem paths (xdg-open /tmp/foobar.png).

Works also on Linux if you install Steam for Windows on Wine.

Support for most major platforms (Windows, Mac, Linux, SteamOS)

I didn't mind 20 bucks because Paradox is one of the most linux-friendly companies out there

there's no ldconfig cache either. So where does bash find libc?

For example, on the terminal I'm using, the right arrow outputs ^[[C. You can see what sequence your terminal outputs by pressing Ctrl-V Right Arrow. The same is true for other cursor-control keys such as Page Up and End.

If you kill ffmpeg process it will exit with code 255 (easily reproducible in the terminal)

man ps has all the answers, under the "PROCESS STATE CODES" heading:

In any case signal handling in shells is one of the least reliable and portable aspects. You'll find behaviours vary greatly between shells and often between different versions of a same shell. Be prepared for some serious hair pulling and head scratching if you're going to try to do anything non-trivial.

Both kill with a job specifier and terminal signals send to the entire process group, so both the shell and sleep.

As usual with almost any command, if you want a normal argument that starts with a - to not be interpreted as a switch, precede it with --

rkill command from pslist package sends given signal (or SIGTERM by default) to specified process and all its descendants:

PGID=$(ps opgid= "$PID") # get the Process Group ID

Typically, a process associated with a controlling terminal is foreground process and its process group is called foreground process group. When you start a process from the command line, it's a foreground process:

Quit the program by sending a different signal to both processes, e.g. SIGQUIT with Ctrl + \.

Why then sending the SIGINT manually to the shell doesn't kill the child, e.g. 'kill -2 <shell-pid>' doesn't do anything to a child process while Ctrl-C kills it?

The shell process itself is in yet another process group all of its own and so doesn't receive the signal when one of those process groups is in the foreground. It's that simple.

Switching "jobs" between foreground and background is (some details aside) a matter of the shell telling the terminal which process group is now the foreground one.

I am trying to understand how CTRL+C terminates a child but not a parent process. I see this behavior in some script shells like bash where you can start some long-running process and then terminate it by entering CTRL-C and the control returns to the shell. Could you explain how does it work and in particular why isn't the parent (shell) process terminated? Does the shell have to do some special handling of CTRL+C event and if yes what exactly does it do?

The CTRL-\ key sends a kill signal to the foreground job which, under normal circumstances, is guaranteed to terminate it. This signal cannot be captured by a process. However, this means the process cannot cleanup and is just summarily stopped. In some cases, a process can be stuck in a kernel wait state so this signal never reaches it. In that case, the process is unusable but cannot be killed.

Also, this code will fail if $$ is not the process group leader, such as when the script is run under strace. Since a call to setsid(2) is probably tricky from a shell script, one approach might be to ps and obtain the process group ID from that.

ps -o pid,pgid,stat,args

When your script starts a process, that child becomes a member of a process group with PGID equal to the PID of the parent process which is $$ in the parent shell.

To accomplish this, after starting the children (loop.sh) in the background, call wait, and upon receipt of the INT signal, kill the process group whose PGID equals your PID.

You need a trap in loop.sh. Traps are cleared for every subshell started unless they are explicitly trap ''SIG ignored by the parent.

ps --forest -o pid,tty,stat,time,cmd -g $(ps -o sid= -p 2795)

To get all the processes spawned by a process the whole tree needs to be built. I used awk for that. At first it builds a hash array to contain all PID => ,child,child... . At the end it calls a recursive function to extract all the child processes of a given process. The result is passed to another ps to format the result.

# Usage: run_with_timeout N cmd args... # or: run_with_timeout cmd args... # In the second case, cmd cannot be a number and the timeout will be 10 seconds. run_with_timeout () { local time=10 if [[ $1 =~ ^[0-9]+$ ]]; then time=$1; shift; fi # Run in a subshell to avoid job control messages ( "$@" & child=$! # Avoid default notification in non-interactive shell for SIGTERM trap -- "" SIGTERM ( sleep $time kill $child 2> /dev/null ) & wait $child ) }

Personally, I prefer signalling an error for invalid values

We can ask timeout to try to stop the program using SIGTERM, and to only send in SIGKILL if SIGTERM didn’t work. To do this, we use the -k (kill after) option. The -k option requires a time value as a parameter.

timeout_child () { trap -- "" SIGTERM; child=$!; timeout=$1; ( sleep $timeout; kill $child; ) & wait $child; } And the usage: ( while true; do echo -n .; sleep 0.1; done) & timeout_child 2

Instead of modifying /usr/share/applications/google-chrome.desktop, the file can be copied into ~/.local/share/applications/google-chrome.desktop and modified without root access. This file will take precedence over the global desktop file.

Systemd targets are reached once and do not fire again when the connection state changes. Depending how your network is managed there are a couple of options:

please, for the love of god do NOT use Mint as a source of inspiration for a derivative distro. If you like Cinnamon or Mate, fine, but holy CHRIST do not let your infrastructure get as criminally sloppy as Mint's. No unholy mixing of Debian and Ubuntu debs into some kind of Frankenbuntu, no namespace collisions, no ... well, no being Mint in general, please!Ideally, I really, really hope you'll continue to support Ubuntu as a primary platform, regardless of what you do with Pop!_OS. But hooboy, do not turn into another Mint, please.

If it was remotely possible to get Davinci Resolve running that would be incredible (and bring a lot of video people I think)

the most productive environment possible for people that use their computer to create.What is a productive environment?How do you measure productivity in an operating system environment?How do you compare YOUR distribution to other distributions when it comes to productivity?Is the way in which 'people that use their computer to create' (creators) the same across all professions and activities?Does a photographer have the same requirements for a productive environment as a software engineer?Why do you think your distribution will be the best for delivering a productive environment than any other Linux distribution?

And then think about if you want a rolling release, or a fixed release. Although all the distros you mentioned are on the fixed release side.

Think about how much you want to customize the desktop environment(DE), and whether you know how to do so. Pick a distro that has the DE you like.

There is no best distro. All of them are more or less the same.

When people talk about "beginner distros" they mean distros that are no hassle to get started, it doesnt mean they are somewhat inferior or less capable.

And honestly, most people prefer the no hassle, especially after wasting too much time dabbling with distros that are "for advanced users" troubleshooting all kinds of dumbass problems that just worked out of the box in many other distros.

considering PopOS is trying to tackle Ubuntu they really need their dual-boot setup to be a lot less tedious

The part where you want to add 2 EFI partitions is not advisable. It seems that Windows doesn't really like this, of you are dual booting multiple Linux installs it might work. But it is always recommended to use only 1 EFI partition per disk. Hope this helps. :)

You don't necessarily have to resize Windows' EFI partition. You can have multiple EFI partitions.

Make a 512MB fat32 partition during manual/custom PopOS install.Select its role as: "/boot/efi" in the PopOS installer.When the OS is installed, type sudo apt install refind and then it should automatically start the installer else type sudo refind-install. This will install rEFInd to your /boot/efi path.

Windows and Linux store their time in the BIOS differently, this will cause your clock to be desynchronized when you switch from one OS to the other. The easiest solution for it is to fix it in Linux, forcing it to work the same way as Windows. You can do this through the terminal:

We recommend the Alpine image as it is tightly controlled and small in size (currently under 5 MB), while still being a full Linux distribution. This is fine advice for Go, but bad advice for Python, leading to slower builds, larger images, and obscure bugs.

1) QT Apps load very slow in startup (ex, qpdfview, Audacious), had to look at Ubuntu forums to find a solution installing kvantum and KvYAru theme, so this is solved at the moment; but the theme (SVG based, cannot modify it in a text file) have orange highlights, not consistent with Mint-Y theme, but it is the best option at the moment. This temporary solution I found was here: https://itectec.com/ubuntu/ubuntu-qt-apps-are-very-slow-to-load-in-xubuntu-20-04-when-export-qt_qpa_platformthemegtk2-is-enabled/

We took a stance on an issue.

Pango is one of the most common font rendering libraries on Linux. It's used by GTK/GNOME and a lot of standalone apps, like Rofi, Polybar, and a lot of terminals.

cp src/glyphs/Symbols-2048-em\ Nerd\ Font\ Complete.ttf ~/.local/share/fonts fc-cache -fv pango-view -t "Playing some  for you right now"

Besides running contrary to the principles that lead a lot of people to Linux systems (a closed store that you can't alter...automatic updates you have no control over....run by just the one company)

Linux on the desktop won't take off until it is equally easy. Snap may be dumbed down, restricted and all the rest of it, but for ordinary users it's easier - and more secure - than the alternative.

>We do want Linux to be mainstream, don't we? Not at any cost.

Think about how native apps work in your favorite desktop operating system. Er, no, not that one. Think about your favorite popular desktop operating system.

Your operating system: Ubuntu 18.04.4 LTS

Welcome to Ubuntu!. It is good to ditch the Windows rubbish and get into the real OS where one can change anything you want, yet have a global community who can support the OS.

The best thing about an open source operating system, such as Linux, is that you can customize it as much as you want, ranging from default applications such as file managers, music players, web browsers, and text editors etc. to more vital system components such as the kernel, display managers, and terminal consoles. You can do this simply by downloading new application software and replacing the old ones with that, or editing system components by making changes in the source code of your operating system. The display manager is one such system component that you can replace simply by running a few commands mentioned in this article.

BlackArch is a Linux distribution designed for penetration testing and security research. You can think of it like Kali Linux, with the exception of being based on Arch Linux. Its official repositories contain more than +2500 various penetration testing tools, and hence it can be considered a very good option for anyone wishing to explore this field and try to hack their own phones/routers/devices during the quarantine time.

Redstar OS is a Fedora-based Linux distribution that was developed to empower all computers running in North Korea. Researchers from various independent teams verified that the distribution contains huge spying mechanisms and logging capability, beside some modified kernel modules to record everything done on the OS.

notifier_call_chain

rsync --info=progress2

Normally Ubuntu swaps files to disk frequently. Since the disk is a microSD card that's a bit slow and has limited write cycles, it's best to reduce swapping to only when needed.

Future kernel updates would require the updated kernels to be signed again, so it makes sense to put the signing commands in a script that can be run at a later date as necessary. A sample script /root/module-signing/sign-vbox-modules is given below.

Windows: Shift + Delete

Linux Memory Management at Scale

echo 256 > /proc/sys/fs/inotify/max_user_instances