Having trouble with rc.local scripting - linux

Hello there Stack Exchange,
I'm trying to use a Raspberry Pi to make a sort of Kiosk display unit out of a TV screen. I figured that this would be a simple enough process, write a startup script that actives LXDE, x11vnc and chromium to the page I want and it's done. But unfortunately, I can't seem to get my rc.local script to work exactly as I want it too and I'm not sure why. This is the code I have added to rc.local
su pi -c startx&
su pi -c x11vnc -display :0 -q -usepw -rfbport 5901
su pi -c chromium --kiosk --incognito "http://www.springwater.ca/"
When the machine is booting it will run the startx command but not the x11vnc or chromium commands. Have I missed something here? Or am I going about this the completely wrong way?
Thanks,
Michael

It will take several seconds before the X server loads and is able to accept connections, but with your &, x11vnc and chromium will try and fail immediately.
After the startx line, you could add a simple sleep 30 to give it time to start, or maybe even poll it:
until xwininfo -root -display :0; do sleep 1; done

i use "nodm" (as package in Debian or from here: http://www.enricozini.org/sw/nodm/) on my Raspberry to login my user and start LXDE. Then autostart all needed applications as described here: http://wiki.lxde.org/en/Autostart.
Edit to answer the comment:
In Debian you can configure the user (and other things) in the file /etc/default/nodm.
I have set the parameter:
# User to autologin for
NODM_USER=dashboard
best wishes,
Matthias

Related

Is there a way to make crontab run a gnu screen session?

I have a discord bot running on a raspberry pi that i need to restart every day, I'm trying to do this through crontab but with no luck.
It manages to kill the active screen processes but never starts an instance, not that I can see with "screen -ls" and I can tell that it doesn't create one that I can't see as the bot itself does not come online.
Here is the script:
#!/bin/bash
sudo pkill screen
sleep 2
screen -dmS discordBot
sleep 2
screen -S "discordBot" -X stuff "node discordBot/NEWNEWNEWN\n"
Here is also the crontab:
0 0 * * * /bin/bash /home/admin/discordBot/script.sh
Is it possible to have crontab run a screen session? And if so how?
Previously I tried putting the screen command stright into cron but now I have it in a bash script instead.
If I run the script in the terminal it works perfectly, it’s just cron where it fails. Also replacing "screen" with the full path "/usr/bin/screen" does not change anything.
So the best way of doing it, without investigating the underlying problem would be to create a systemd service and putting a restart command into cron.
 
/etc/systemd/system/mydiscordbot.service:
[Unit]
Description=A very simple discord bot
[Service]
Type=simple
ExecStart=node /path/to/my/discordBot.js
[Install]
WantedBy=multi-user.target
Now you can run your bot with systemctl start mydiscordbot and can view your logs with journalctl --follow -u mydiscord bot
Now you only need to put
45 2 * * * systemctl restart discordbot
into root's crontab and you should be good to go.
You probably should also write the logs into a logfile, maybe /var/log/mydiscordbot.log, but how and if you do that is up to you.
OLD/WRONG ANSWER:
cron is run with a minimal environment, and depending on your os, /usr/bin/ is probably not in the $PATH var. screen is mostlikely located at /usr/bin/screen, so cron can't run it because it can't find the screen binary. try replacing screen in your script with /usr/bin/screen
But the other question here is: Why does your discord bot need to be restarted every day. I run multiple bots with 100k+ users, and they don't need to be restarted at all. Maybe you should open a new question with the error and some code snippets.
I don't know what os your rpi is running, but I had a similar issue earlier today trying to get vms on a server to launch a terminal and run a python script with crontab. I found a very easily solution to automatically restart it on crashes, and to run something simply in the background. Don't rely on crontab or an init service. If your rpi as an x server running, or anything that can be launched on session start, there is a simple shell solution. Make a bash script like
while :; do
/my/script/to/keep/running/here -foo -bar -baz >> /var/log/myscriptlog 2>&1
done
and then you would start it on .xprofile or some similar startup operation like
/path/to/launcher.sh &
to have it run the background. It will restart automatically everytime it closes if started in something like .xprofile, .xinitrc, or anything ran at startup.
Then maybe make a cronjob to restart the raspberry pi or whatever system is running the script but this script wil restart the service whenever it's closed anyway. Maybe you can put that cronjob on a script but I don't think it would launch the GUI.
Some other things you can do to launch a GUI terminal in my research with cronjob that you can try, though they didn't work for my situation on these custom linux vms, and that I read was a security risk to do this from a cronjob, is you can specify the display.
* * * * * DISPLAY=:0 /your/gui/stuff/here
but you would would need to make sure the user has the right permissions and it's considered an unsafe hack to even do this as far as I have read.
for my issue, I had to launch a terminal that stayed open, and then changed to the directory of a python script and ran the script, so that the local files in directory would be called in the python script. here is a rough example of the "launcher.sh" I called from the startup method this strange linux distro used lol.
#!/bin/sh
while :; do
/usr/bin/urxvt -e /bin/bash -c "cd /path/to/project && python loader.py"
done
Also check this source for process management
https://mywiki.wooledge.org/ProcessManagement

Minecraft Linux Server | Start.sh problem

I have a Minecraft Server running on Linux.
I use to start the server, a start.sh file with following content:
(This content starts a screen session and the minecraft server)
screen -S {ScreenSession} java -Xmx2G -Xms2G -jar spigot-1.18.1.jar
If I use /restart ingame, the screen session will end and the server won't start. So I have to go into the Linux Server and start the Minecraft Server again.
My question:
How can I make it so, if I use /restart that the server will restart with a active screen session.
If have tried many things.
I hope someone can help me,
~Kitty Cat Craft
There is multiple way to achieve what you want.
If you have lot of servers, you can use a quick bash script with an auto restart like that:
#!/bin/sh
while true
do
java -Xmx2G -Xms2G -jar spigot-1.18.1.jar --nogui
sleep 5
done
When you will stop, it will wait 5 seconds then restart.
With this, you can use: screen -dmS <screenName> sh myScript.sh which will run the script into another screen. It's usefull when you run it from a script which run lot of server, like that:
screen -dmS srv1 sh srv1.sh
screen -dmS srv2 sh srv2.sh
screen -dmS srv3 sh srv3.sh
You can also, if you have only one server, just firstly use screen -S screenName. Then, when you are in the screen, run the script that restart automatically (the script that I gave at first).
Also, prefer use /stop than /restart, because spigot will try to find the script. And if it success, it will run a second time the same script, and so will have ghost process.

Linux - shutdown-script with SSH

I would like to make a shutdown-script for my raspberry pi to shut down anothe raspberry pi over ssh.
The script works if it is running itself but at the shutdown routine the ssh command is not executed.
So that I have done until now:
Made the script in /etc/init.d:
#!/bin/sh
# the first thing is to test if the shutdown script is working
echo "bla bla bla " | sudo tee -a /test.txt
ssh pi#10.0.0.98 sudo shutdown -h now
Made it executable
sudo chmod +x /etc/init.d/raspi.sh
Made a symlink to the rc0.d
sudo ln -s /etc/init.d/raspi.sh /etc/rc0.d/S01raspi.sh
Now I know so far that the shutdown script is working outside of the shutdown routing by calling itself and the shutdown symlink I made is also working partially because I see the changes in the test.txt file every time I shut down.
Can anyone help me how to solve my problem?
Have you tried with single quotes?
The first link in Google has it
http://malcontentcomics.com/systemsboy/2006/07/send-remote-commands-via-ssh.html
What about the sudo, how do you solve entering the password?
https://superuser.com/questions/117870/ssh-execute-sudo-command
Please check this or other links on the web that have useful information.
I would have send all this in a comment but I cant yet because of reputation.
I have now got the script running by myself. I do not really know why it is now working but I write it down beneath and maybe someone else can clearifiy it.
I don´t think the first two changes at my system makes a difference but I also write it down. In the meanwhile because I do not managed the script to get working I had made a button to shutdown the system manually. Also I made a script which backs the mysql-database up (which is on the Raspberry Pi which I would like to switch off with the script) and copies the backup to the raspberry pi which should switch of the other raspberry automatically via the shutdown-script. This happens with scp and also for the password is a key generated.
I have also changed my script to get a log-message out of the script.
#!/bin/sh
ssh -t -t pi#10.0.0.99 'sudo shutdown -h now' >> /home/osmc/shutdown.log 2>&1
To get it into the shutdown-routine I used:
sudo update-rc.d raspi-b stop 01 0
I hope somebody can say me why my code now worked on the first day but not on the next few days until now.
I structured a command to suspend or shutdown a remote host over ssh. You may find this useful. This may be used to suspend / shutdown a remote computer without an interactive session and yet not keep a terminal busy. You will need to give permissions to the remote user to shutdown / suspend using sudo without a password. Additionally, the local and remote machines should be set up to SSH without an interactive login. The script is more useful for suspending the machine as a suspended machine will not disconnect the terminal.
local_user#hostname:~$ ssh remote_user#remote_host "screen -d -m sudo pm-suspend"
source: कार्यशाला (Kāryaśālā)

Run a script after killing lxsession (xorg)

I am trying to run a program automatically within a bash script after killing the LXDE session. My script consists of:
#!/bin/sh
pkill lxsession;
sh /home/pi/RetroPie/EmulationStation/emulationstation
I tried this as well:
#!/bin/sh
nohup & pkill lxsession &
writevt /dev/tty1 'emulationstation'
My aim is to log out of the LXDE session and run EmulationStation on my Raspberry Pi with a bash script. I'm using pkill lxsession; to bypass lxsession's logout confirmation dialog.
As it stands, this script just gets me to the command line from a working LXDE desktop. Thanks for reading.
Dont EmulationStation need some sort of X server running in the background for it to work?
IF not, then try the following:
#!/bin/sh
pkill lxsession;
sleep 5
su -c sh /home/pi/RetroPie/EmulationStation/emulationstation
exit
It could also be that when you log out of your lxde session the emulationstation dosent have a usershell to open it, therefore "su -c"
I'm not sure if its going to work but I hope you solve it. :)

Using SSH to open application on desktop

So normally people ask how to forward x11 to the local machine, but rather I want to leave the application running on the remote box's desktop.
So let say I ssh from a windows machine (using putty) and run xclock & disown. If I then walked over to my desktop and look at the screen and see xclock running on the linux machine.
Any way to do that? Using Mint 13.
This works for me once I'm ssh'd in:
export DISPLAY=:0; nohup <command> &>/dev/null &
For example:
export DISPLAY=:0; nohup iceweasel &>/dev/null &
When you're ssh'd in normally, set the DISPLAY variable with export DISPLAY=0:0 (0:0 being the display of the target box), and then you can run your command as you normally would. If you want to be able to close the ssh session, prepend the command with nohup: nohup ./yourcommand > dev/null.
h4bo --> That worked. just had to make the script.
First part of learning ssh stuff. Now instead of leaving teamviewer (a remote desktop program) open all the time, I can launch when I need it and then use it.
i guess
nohup ssh -X <ip address> <application name>
I recently had to do some python tkinter development on a Raspberry Pi with Thonny, where I wanted the tkinter graphics to show on the Pi's X server. For this specific purpose, I created a /usr/bin/pythonx script which simply consisted of:
#!/bin/bash
DISPLAY=:0 python "$#"
This wrapping technique works when Thonny ssh's into the Pi where the user is also logged in at the GUI desktop, as the ssh user has access to the .Xauthority data needed to send X client requests (application) to the server (GUI).

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