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I have been having troubles setting up an auto reboot for my mc server.

My .sh file I have made works perfectly whenever I execute it, but when it comes to using crontab it seems to just do nothing (excluding one time), I have tried restarting & reinstalling it... it is safe to say I am out of my element as I am completely new to all of this.

The crontab line is this

0 20 * * * /VHServer/reboot.sh

nothing has changed since I made that line of code, it worked the first time and then never again.

The .sh file looks like this and it runs perfectly with a manual command.


echo "Server reboot STARTED"

Letting people know that the server is going to restart


tmux send-keys -t VHS "/say §c Server restarting in §r§6§l30 minutes. §r§cPleas>


Wait for 1770 seconds (25 minutes)


sleep 1500s


Send messages to the server indicating the restart countdown


tmux send-keys -t VHS "/say §c Server is restarting in §r§6§l5 minutes! §r§cThe>
sleep 270s


tmux send-keys -t VHS "/say §c Server is restarting in §r§6§l30 seconds! §r§cTh>
sleep 20s


tmux send-keys -t VHS "/say §c Server is restarting in §r§6§l10 seconds!" Enter
sleep 5s


tmux send-keys -t VHS "/say §c Server is restarting in §r§6§l5 seconds!" Enter
sleep 1s


tmux send-keys -t VHS "/say §c Server is restarting in §r§6§l4 seconds!" Enter
sleep 1s


tmux send-keys -t VHS "/say §c Server is restarting in §r§6§l3 seconds!" Enter
sleep 1s


tmux send-keys -t VHS "/say §c Server is restarting in §r§6§l2 seconds!" Enter
sleep 1s


tmux send-keys -t VHS "/say §c Server is restarting in §r§6§l1 second!" Enter
sleep 1s


Stop the Minecraft server


tmux send-keys -t VHS "/stop" Enter
sleep 60s


Detatch from the tmux session


tmux send-keys VHS C-b d
sleep 15s


Check if the session exists and kills session


if tmux has-session -t VHS> /dev/null; then
    echo "Killing tmux session 'VHS'."
    tmux kill-session -t VHS
else
    echo "Tmux session 'VHS' does not exist."
fi
sleep 15s


Check if a session with the same name already exists


if tmux has-session -t VHS> /dev/null; then
    echo "Tmux session 'VHS' already exists. Attaching to it."
    tmux attach-session -t VHS
else
    echo "Creating new tmux session 'VHS'."
    tmux new-session -s VHS
fi
sleep 30s


Restart the server using the run.sh script


tmux send-keys -t VHS "/home/ubuntu/VHServer/run.sh" Enter


echo "Server Rebooting"
sleep 60s


echo  "reboot COMPLETE"

I have had suggestions to run the crontab using sudo and also adding either sudo or the username "ubuntu" to the line of code within it, I have tried and there has been no output whatsoever.

I ran:

tail -f /var/log/syslog

and this only came back with the edits of the crontab, not once did the cron execute any command.

I hope this is enough information to provide a fix, I am at a complete loss and still learning about all of this, so I am sure I am not understanding something within all of this.

PerplexApple
  • 1
  • cron will discard any output unless you redirect the output of each command like echo "Server Rebooting" &>> /home/ubuntu/logfile or the whole script in crontab like 0 20 * * * /VHServer/reboot.sh &>> /home/ubuntu/logfile ... See also https://askubuntu.com/a/1448126 and https://askubuntu.com/a/1452020 – Raffa Jun 11 '23 at 09:59
  • ... unless your crontab explicitly sets SHELL=/bin/bash, use /VHServer/reboot.sh >> /home/username/logfile 2>&1 though - the default is to run crontab jobs in /bin/sh which won't recognize &>> as stdout+stderr redirection – steeldriver Jun 11 '23 at 12:26

1 Answers1

3

Your script should begin with:

#!/bin/bash

Replace tmux with the absolute path (type -p tmux). cron jobs have a different runtime environment, different $PATH, no $DISPLAY, etc. Read man -a crontab.

waltinator
  • 36,399
  • the script does begin with #!/bin/bash I failed to copy that in sorry!

    I have done as explained, changed all the "tmux" commands to the path type -p tmux provided which looked like this: /usr/bin/tmux"

    The crontab seems to still have no output.

     – PerplexApple Jun 11 '23 at 08:15