Answer by Raul Baron for Cron job to run on the last day of the month

What about this?

edit user's .bashprofile adding:

export LAST_DAY_OF_MONTH=$(cal | awk '!/^$/{ print $NF }' | tail -1)

Then add this entry to crontab:

mm hh * * 1-7 [[ $(date +'%d') -eq $LAST_DAY_OF_MONTH ]] && /absolutepath/myscript.sh