Questions[signal](ubuntu)

When you open gnome-terminal without any options and execute a blocking command (e.g. python3, vim or cat) and then try to close the window by the close button (i.e. x button in the title bar) or some keyboard shortcut, a confirmation window is displayed:

However, when you open gnome-terminal with an executed command specified, that is, in the form of gnome-terminal -- python3, the confirmation window is no longer displayed and the window is closed right after you (accidentally) click the close button.

Is it possible to show the confirmation window even when you use the form gnome-terminal -- <command>? If that's impossible, is there any workarounds?

Environments:

$ gnome-terminal --version
# GNOME Terminal 3.36.2 using VTE 0.60.3 +BIDI +GNUTLS +ICU +SYSTEMD

What I've Tried:

• Equipping the executed command with signal handlers for all the supported signals didn't work; the window was still closed without confirmation although the process survived the closure while catching SIGHUP (three times), SIGCONT (once) and SIGWINCH (once). I had additionally to execute kill -SIGKILL <process id> to kill the process.

• I found one exception. When you execute gnome-terminal -- bash, the confirmation is displayed (though this is by default the same as gnome-terminal).

I am trying to understand the reason why the whole Python process does not get killed when I press Ctrl + C inside and infinite loop or for that matter any Python function that I am running in terminal and only the loop/function is stopped?

Question

Do you know any tool/script to send SIGSTOP (to pause a process) or SIGCONT (to resume it) to a process by clicking on a graphical window generated by the process?

Some context

There is already a tool called xkill which kills programs by clicking on a window, but it has no options to send a particular signal. This is a pity, because somewhat related command-line tools like kill have this option.

Usually I do this via command line by manually obtaining the corresponding process names and using tools like kill, pkill or killall but it would be nice to be able to do this graphically, in a way similar to clicking on a window with the xkill tool.

Applications

I would find such a tool very useful to graphically pause some heavy processes when the CPU is too "stressed" without terminating them and without losing data which cannot be saved (e.g. for partial results of long calculations).

I am new to Node, JavaScript etc. and want to try messing with the code of Signal. For this I need a specific version of Node. I did this (on Ubuntu 16.04) using the following procedure:

wget https://nodejs.org/dist/v8.2.1/node-v8.2.1-linux-x64.tar.gz
sudo mkdir -p /opt/nodejs
sudo tar -xvzf node-v8.2.1-linux-x64.tar.gz -C /opt/nodejs/
cd /opt/nodejs/
sudo mv node-v8.2.1-linux-x64 8.2.1
sudo ln -s 8.2.1 current
sudo ln -s /opt/nodejs/current/bin/node /bin/node
mode -v

I then installed NPM:

sudo apt install npm

I then started working through the setup steps for Signal:

sudo npm install --global yarn
sudo yarn install --frozen-lockfile
sudo yarn grunt

When I run this last command, I see that an incorrect version of Node is being used and then encounter an error:

yarn run v1.5.1
warning You are using Node "4.2.6" which is not supported and may encounter bugs or unexpected behavior. Yarn supports the following semver range: "^4.8.0 || ^5.7.0 || ^6.2.2 || >=8.0.0"
error An unexpected error occurred: "Couldn't find a package.json file in \"/opt/nodejs\"".
info If you think this is a bug, please open a bug report with the information provided in "/opt/nodejs/yarn-error.log".
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

What is going wrong?

I often have to run the update manager on a slow connection, and while reading my emails, I meanwhile would like to surf for 2 minutes in the web, then have the full bandwidth again for the update manager.

From the command line, I can suspend a running process with Ctrl+Z, aka suspend. But if I didn't start the program from the shell - can I do it with some signal and the kill command?

I read the man page for signal (man -a signal), but there I didn't find a SIGSUSPEND, only SIGSTOP, SIGTERM, SIGINT and such - which is appropriate, or is there none?