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Context

Suppose one would like a single Bash installation script named install.sh to ensure Ubuntu 22.04 runs the command: picard (which launches a GUI), at boot (in the background, without showing the GUI).

Approach

I looked at: https://askubuntu.com/a/816/846880 which allows one to do this manually by typing:

crontab -e
[1] (to select the favourite editor)
@reboot /path/to/script

However, I would like the cronjob to be set up automatically instead of manually. So I looked in GitHub: and found this install script which contains:

#para crontab -e
#echo "@reboot sudo /home/pi/ili9342-driver/fbcp-ili9342" >> mycron; crontab mycron;rm mycron

Issue

However, that does not take into account whether the desired line already is in the crontab.

Question

Hence, I was wondering to know how to make a single Bash script automatically run the command picard at boot? (Ideally in the background without showing the GUI)

a.t.
  • 387

1 Answers1

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The answer below does not yet run picard at the background, nor did I write unit tests for it. It does however automatically set up a crontab at reboot from a bash script.

run_tribler_at_boot() {
    local git_dir="$1"

# Create cronjob command
cron_command="@reboot $git_dir/tribler/src/./tribler.sh  > tribler.log"

# Check if crantab contains run at boot line already:
found_cron_command=$(crontab -l | grep "$cron_command")
if [ "$found_cron_command" == "" ]; then

    # Add cronjob to crontab if it is not in yet.
    write_cronjob "$git_dir" "tribler_cron" "$cron_command"
elif [ "$found_cron_command" == "$cron_command" ]; then
    echo "cronjob is already in crontab."
else
    echo "Error, the cronjob was not correctly in the crontab"
    echo "(most likely the cron_command:$cron_command is in in duplo):"
    echo ""
    crontab -l
    echo ""
    echo "Remove the (duplicate) cron_command(s) from the crontab -e"
    echo "and try again."
    exit 6
fi




}


write_cronjob() {
    local git_dir="$1"
    local temp_cronjob_filename="$2"
    local cron_command="$3"


# Write out the current crontab into a new file with filemname in var mycron.
crontab -l > $temp_cronjob_filename

#echo new cron into cron file through append.
echo "$cron_command" >> $temp_cronjob_filename

#install new cron file
crontab $temp_cronjob_filename


# TODO: Verify the temp_cronjob_filecontent equals the crontab -e output.
#rm $temp_cronjob_filename



}

And it can be called with:

run_tribler_at_boot() "~/git"

Assuming the application, in this case tribler, is stored into ~/git/tribler/src/tribler.sh To change to picard the cron_command can be set to:

cron_command="@reboot picard"

I did not yet figure out how to run it in the background.

a.t.
  • 387