#write out current crontab
crontab -l > mycron
#echo new cron into cron file
echo "00 09 * * 1-5 echo hello" >> mycron
#install new cron file
crontab mycron
rm mycron
$(crontab -l && echo "0 0 0 0 0 some entry") | crontab -
crontab -l; echo "*/30 * * * * speedtest-cli --share > /path/to/NetSpeed/$(date | cut -d " " -f 2-4 | tr ' ' '-')"; crontab -
* * * * * "command to be executed"
- - - - -
| | | | |
| | | | ----- Day of week (0 - 7) (Sunday=0 or 7)
| | | ------- Month (1 - 12)
| | --------- Day of month (1 - 31)
| ----------- Hour (0 - 23)
------------- Minute (0 - 59)