Enable autostart

Back to Robobot B

Autostart

Start app to display IP on Regbot display, log CPU temperature and synchronize hostname

Make an on-reboot script in the home directory

cp ~/svn/robobot/setup/on_reboot.bash ~/

This file is something like:

#!/bin/bash
# script to start applications after a reboot
#
# Run the app to show Raspberry's IP on the Teensy display and start button.
mkdir -p /home/local/svn/log
cd /home/local/svn/log
# save the last reboot date
echo "Rebooted" >> rebootinfo.txt
date >> rebootinfo.txt
../robobot/ip_disp/build/ip_disp &
# save PID for debugging
echo "ip_disp started with PID:" >> rebootinfo.txt
pgrep -l ip_disp >> rebootinfo.txt
#
# start camera server
cd /home/local/svn/robobot/stream_server
/usr/bin/python3 stream_server.py &
echo "python3 cam streamer started with PID:" >> rebootinfo.txt
pgrep -l python3 >> rebootinfo.txt
exit 0

Use crontab to run this script at reboot.

crontab -e

If asked, select the preferred editor (suggesting nano).

Add this line at the end:

@reboot /home/local/on_reboot.bash

Hostname update

A script updates the Raspberry Pi hostname, with the name in ~/svn/log/robotname. The script rename_host.bash is:

#!/bin/bash
hn=`hostname`
f="/home/local/svn/log/robotname"
if [ -f $f ]; 
then # file exist
 # get (new) name in file to variable nn
 nn=`cat $f`
 echo "found name " $nn
 yy=$(expr length $nn)
 if [ $yy -gt 2 ];
 then # length is longer than 2 characters
   if [ $hn != $nn ]; 
   then # replace old hostname with new
     echo ++++++++++ >> rebootinfo.txt
     date >> rebootinfo.txt
     echo new name is $nn, so rename host from $hn >> rebootinfo.txt
     hostnamectl set-hostname $nn
     sed -i "s/$hn/$nn/g" /etc/hosts
   fi
 fi
else
 echo "File >" $f "< not found."
fi

The script needs to be run as root; therefore, it is set to run as part of the boot process.

Create the script in /etc/init.d

sudo nano /etc/init.d/host_rename.bash

Enter the following lines into the new file.

#!/bin/bash
bash /home/local/svn/robobot/setup/rename_host.bash

Make the file executable and add it to run-level 2 (before networking is started)

sudo chmod +x /etc/init.d/host_rename.bash
sudo ln -s /etc/init.d/host_rename.bash /etc/rc2.d/S99host_rename

The script is then executed when the Raspberry boots, and if the hostname does not match that of the Teensy, then the hostname is modified.

If the name changes, the script notes it in the file '/home/local/svn/log/rebootinfo.txt' (owned by 'root').