To install as an hourly cronjob, define $path_to_pingmail_script_file, then do:
-line='0 * * * * '$path_to_pingmail_script_file' check'
-(crontab -l; echo $line) | crontab -
+line='0 * * * * '$path_to_pingmail_script_file' check > /dev/null'
+(crontab -l; echo "$line") | crontab -