Check if my cronJob already exist
Put my cronJob if it does not already exist
or
update my cronjob if one of the parameter of the command is different

if [[ $(crontab -l | egrep -v "^(#|$)" | grep -q 'something'; echo $?) == 1 ]]
then
    echo $(crontab -l ; echo '* 1 * * * something') | crontab -
fi

echo "* 1 * * * something" | crontab -

echo "* 1 * * * something" | ssh user@host "crontab -"

# on the machine itself
echo "$(echo '* 1 * * * something' ; crontab -l)" | crontab -
# via ssh
echo "$(echo '* 1 * * * something' ; ssh user@host crontab -l)" | ssh user@host "crontab -"

echo '0 0 * * 0 webadmin /usr/local/bin/tidy_logfiles' > ~/webadmin.cron
scp -p ~/webadmin.cron root@remote_host:/etc/cron.d/webadmin

ssh -q root@remote_host rm -f /etc/cron.d/webadmin

unset VISUAL
EDITOR='update_crontab () {
  set -e
  new=$(mktemp)
  if <"$1" grep -v "^#" | grep -w do_stuff; then
    # Remove existing entries containing do_stuff
    grep -v -w do_stuff "$1" >"$new"
  else
    cp "$1" "$new"
  fi
  # Add the new entry
  echo "1 2 3 4 5 do_stuff --new-options" >>"$new"
  mv "$new" "$1"
}
update_crontab' crontab -e