Due to some issues I wont elaborate here to not waste time, I made a bash script which will ping google every 10 minutes and if there is a response it will keep the loop running and if not then the PC will restart. After a lot of hurdle I have been able to make the script and also make it start on bootup. However the issue is that i want to see the results on the terminal, meaning I want to keep monitoring it but the terminal does not open on bootup. But it does open if I run it as ./net.sh.
The script is running on startup, that much I know because I use another script to open an application and it works flawlessly.
My system information
NAME="Linux Mint"
VERSION="18.3 (Sylvia)"
ID=linuxmint
ID_LIKE=ubuntu
PRETTY_NAME="Linux Mint 18.3"
VERSION_ID="18.3"
HOME_URL="http://www.linuxmint.com/"
SUPPORT_URL="http://forums.linuxmint.com/"
BUG_REPORT_URL="http://bugs.launchpad.net/linuxmint/"
VERSION_CODENAME=sylvia
UBUNTU_CODENAME=xenial
The contents of my net.sh bash script are
#! /bin/bash
xfce4-terminal &
sleep 30
while true
do
ping -c1 google.com
if [ $? == 0 ]; then
echo "Ping Sucessful. The Device will Continue Operating"
sleep 600
else
systemctl reboot
fi
done
I have put the scripts in /usr/bin and inserted the scripts for startup at boot in /etc/rc.local
So I did some further research and with help from reddit I realized that the reason I couldnt get it to show on terminal was because the script was starting on bootup but I needed it to start after user login. So I added the script on startup application (which can be found searching on start menu if thats whats it called). But it was still giving issues so I divided the script in two parts.
I put the net.sh script on startup and directed that script to open my main script which i named net_loop.sh
This is how the net.sh script looks
#! /bin/bash
sleep 20
xfce4-terminal -e usr/bin/net_loop.sh
And the net_loop.sh
#! /bin/bash
while true
do
ping -c1 google.com
if [ $? == 0 ]; then
echo "Ping Sucessful. The Device will Continue Operating"
sleep 600
else
systemctl reboot
fi
done
The results are the results of the net_loop.sh script are open in another terminal.
Note: I used help from this thread
If minute interval is usable why not use "cron" to start your?
$> crontab –e
or
$> sudo crontab –e
Related
I'm trying to write a bash script.
The script should check if the MC server is running. If it crashed or stopped it will start the server automatically.
I'll use crontab to run the script every minute. I think I can run it every second it won't stress the CPU too much. I also would like to know when was the server restarted. So I'm going to print the date to the "RestartLog" file.
This is what I have so far:
#!/bin/sh
ps auxw | grep start.sh | grep -v grep > /dev/null
if [ $? != 0 ]
then
cd /home/minecraft/minecraft/ && ./start.sh && echo "Server restarted on: $(date)" >> /home/minecraft/minecraft/RestartLog.txt > /dev/null
fi
I'm just started learning Bash and I'm not sure if this is the right way to do it.
The use of cron is possible, there are other (better) solutions (monit, supervisord etc.). But that is not the question; you asked for "the right way". The right way is difficult to define, but understanding the limits and problems in your code may help you.
Executing with normal cron will happen at most once per minute. That means that you minecraft server may be down 59 seconds before it is restarted.
#!/bin/sh
You should have the #! at the beginning of the line. Don't know if this is a cut/paste problem, but it is rather important. Also, you might want to use #!/bin/bash instead of #!/bin/sh to actually use bash.
ps auxw | grep start.sh | grep -v grep > /dev/null
Some may suggest to use ps -ef but that is a question of taste. You may even use ps -ef | grep [s]tart.sh to prevent using the second grep. The main problem however with this line is that that you are parsing the process-list for a fairly generic start.sh. This may be OK if you have a dedicated server for this, but if there are more users on the server, you run the risk that someone else runs a start.sh for something completely different.
if [ $? != 0 ]
then
There was already a comment about the use of $? and clean code.
cd /home/minecraft/minecraft/ && ./start.sh && echo "Server restarted on: $(date)" >> /home/minecraft/minecraft/RestartLog.txt > /dev/null
It is a good idea to keep a log of the restarts. In this line, you make the execution of the ./start.sh dependent on the fact that the cd succeeds. Also, the echo only gets executed after the ./start.sh exists.
So that leaves me with a question: does start.sh keep on running as long as the server runs (in that case: the ps-test is ok, but the && echo makes no sense, or does start.sh exit while leaving the minecraft-server in the background (in that case the ps-grep won't work correctly, but it makes sense to echo the log record only if start.sh exits correctly).
fi
(no remarks for the fi)
If start.sh blocks until the server exists/crashes, you'd be better off to simply restart it in an infinite loop without the involvement of cron. Simply type in a console (or put into another script):
#!/bin/bash
cd /home/minecraft/minecraft/
while sleep 3; do
echo "$(date) server (re)start" >> restart.log
./start.sh # blocks until server crashes
done
But if it doesn't block (i.e. if start.sh starts the server and then returns, but the server keeps running), you would need to implement a different check to verify if the server is actually still running, other than ps|grep start.sh
PS: To kill the infinite loop you have to Ctrl+C twice: Once to stop ./start.sh and once to exit from the immediate sleep.
You can use monit for this task. See docu. It is available on most linux distributions and has a straightforward config. Find some examples in this post
For your app it will look something like
check process minecraftserver
matching "start.sh"
start program = "/home/minecraft/minecraft/start.sh"
stop program = "/home/minecraft/minecraft/stop.sh"
I wrote this answer because sometimes the most efficient solution is already there and you don't have to code anything. Also follow the suggestions of William Pursell and use the init system of your OS (systemd,upstart,system-v,etc.) to host your scripts.
Find more:
Shell Script For Process Monitoring
I am using guestcontrol with Virtual Box with a Windows host and a Linux (RHEL7) guest. I want to do some config from the host to the guest by running a shell script on the guest (from a .bat on the host). This is fine and the script runs, however, it hangs when I call the reboot (I believe it is because nothing is returned). So when the following .sh is called:
#!/bin/bash
echo "here"
exit
The .bat file shows "here" and then exits (or if I use pause gives the correct message). However, when I add the reboot, the .bat never processes anything past where it calls the script. I think this would be because the guest never tells the host that the script is complete.
I have tried things like:
#!/bin/bash
{ sleep 1; reboot; } >/dev/null &
exit
or even:
#!/bin/bash
do_reboot(){
sleep 1
reboot
}
do_reboot() &
exit
but the .bat never gets past the line where it runs the .sh
How can I tell the host that the .sh script (on the guest) is complete so it can continue with the .bat script?
We need to make sure there are no sub processes running, so we want to do a no heads up using the nohup command. So the script simply becomes this:
#!/bin/bash
nohup reboot &> /tmp/nohup.out </dev/null &
exit
The stdin and stdout were causing the issues, so this just sends them into the void so that the script will not be waiting for any input from any other processes.
If you have any issues with this script, you could do something like:
#!/bin/bash
nohup /path/to/reboot_delay.sh &> /tmp/nohup.out </dev/null &
exit
And then in /path/to/reboot_delay.sh you would have:
#!/bin/bash
sleep 10 # or however many seconds you need to wait for something to happen
reboot
This way you could even allow some time for something to finish etc, yet the host machine (or ssh or wherever you are calling this from) would still know the script had finished and do what it needs to do.
I hope this can help people in future.
I wrote a simple script to ceck if the deluge demon is running and if not to restart it:
#!/bin/bash
if [[ $(pidof deluged | wc -1) -eq 0 ]]; then
deluged
fi
I added it to scheduled job on cron to make it run every 5 minutes...everything work fine, if I kill the deluge demon (deluged) my script restart it correctly.
My problem is that one:
I'm using deluge to download torrents, but sometimes it lost the connection with the localhost (127.0.0.1) and periodically I have to check if it still running, how can I improve the above code to automatically reconnect to the host?
Thanks!
I've been experimenting with Pis for a little while now and am close to completing my first project, I have all the bits working but I'm struggling to put them all together into an automated process.
Basically I have a Pi setup to run a fbi slideshow from a specific folder and I want it to constantly be looking for a pre established Wifi network and when it finds this network it needs to run an update script. I've got these two bits working.
From here, I want the Pi to be turned on and load straight into fbi whilst running the checking script in the background, if the checking script finds the Wifi network then it will run as normal (preferably without ending the slideshow) and when it's done fbi should have an updated selection of images to run (if a restart of fbi is necessary then so be it).
I'm coming up short on achieving this. I can run one script or the other, and if I automate the checking script (cron hasn't worked though I dare say I'm doing something wrong) with rc.local it just gets stuck in a checking loop before login, which kinda makes sense given the script.
Here's the monitoring script:
#!/bin/bash
while true ; do
if ifconfig wlan0 | grep -q "inet addr:" ; then
echo "Wifi connected!"
echo "Initiating Grive sync!"
(cd /home/pi/images/; ./grive -s Pi_Test -V)
sleep 60
else
echo "Wifi disconnected! Attempting to reconnect now."
ifup --force wlan0
sleep 10
fi
done
and in case it's relevant, here's the command the run the fbi slideshow:
fbi -noverbose -a -t 10 -u /home/pi/images/Pi_Test/*.jpg
I do not have a Pi but I have used cron on my VPS which is running a CentOS, but the overall procedure should be similar.
To have some script to be executed by cron, you need to:
Edit /etc/cron.allow
You need to add in your user id to this file so that you can use crontab.
crontab -e
Use this command to add rules you want to fire.
From your description, it seems to me that you already know the syntax to add rules into cron table.
After that, you can use crontab -l to verify your change.
As for stuck at before login, that is very likely due to the while loop. You might want to get rid of the while and sleep because cron is helping you out by invoking your script periodically.
Therefore the following should not suffer from the stuck issue.
if ifconfig wlan0 | grep -q "inet addr:" ; then
echo "Wifi connected!"
echo "Initiating Grive sync!"
(cd /home/pi/images/; ./grive -s Pi_Test -V)
else
echo "Wifi disconnected! Attempting to reconnect now."
ifup --force wlan0
fi
The trick instead, is to have some line similar to this in your cron table
*/1 * * * * /home/David_Legassick/test.sh
The */1 asks cron to call your script test.sh every minute.
ssh user#myserver.com<<EOF
cd ../../my/path/
sh runscript.sh
wait
cd ../../temp/path
sh secondscript.sh
EOF
The first script runs and asks me the questions in that script, but before i'm even able to start typing to answer them the second script starts running. From what I'm reading this shouldn't be happening even without the wait.