[Script] automatically crontab update

Sometimes you need to update a crontab configuration in multiple enviroments (staging, production...).


If you have properly configured ssh, you can use this shell function:

function addToCrontabIfNotAlreadyPresent() {

HOST=$1



ssh -o "BatchMode yes" $USER@$HOST  << EOF



    crontab_line="5 0 * * * cd ~/yourproject/ && ./script/run.sh >/dev/null 2>&1-" 

    alreadyInCrontab="\$(crontab -l | grep "\$crontab_line" )"

    

    if test "\$alreadyInCrontab" == ""; then

       crontab -l > /tmp/updating_crontab.tmp

       echo "\$crontab_line" >> /tmp/updating_crontab.tmp

       crontab /tmp/updating_crontab.tmp

       rm /tmp/updating_crontab.tmp

       

       echo "Crontab updated"; 

    else 

       echo "Crontab ok"; 

    fi

EOF

}



USER='your_user'

addToCrontabIfNotAlreadyPresent "10.10.10.10"