Very helpful website top figure out crontab sequence
https://crontab.guru/#0_0_*_*_*
Every 30 minutes
/etc/crontab
*/30 * * * * root /etc/init.d/httpd restart > /dev/null 2>&1
*/30 * * * * root /etc/init.d/mysql restart > /dev/null 2>&1
Every hour
/etc/crontab
0 * * * * root /etc/init.d/httpd restart > /dev/null 2>&1
Every minute
/etc/crontab
* * * * * root /etc/init.d/httpd restart > /dev/null 2>&1
Check logs
tail n- 200 /var/log/cron
tail n- 200 /var/log/messages
Plus link here regarding dev/null 2>&1
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