Crontab for scheduled task execution in linux

In linux, the crontab switch value is crontab-u username-e. the root user executes crontab-u username-e. // set the scheduled task for username with Hu.
In the pop-up editing box, enter a scheduled task, for example, 0 */2 *** echo "Have a break now every two hours. ">/tmp/test.txt every two hours from PM to am, 8 *** echo "Have a good dream :)">/tmp/test.txt: 4 every month and www.2cto.com 0 11 4*1 from Monday to Wednesday of every week -3 command line a.m. on October 11, January 1 4 1 1 * command line time settings we have certain conventions, the first five digits * represent five numbers. The value range and meaning of the numbers are as follows: minute (0-59) hour (0-23) Date (1-31) month (1-12) Week (0-6) // 0 represents Sunday. In addition to numbers, there are also several special symbols "-",", ", * indicates all numbers in the value range. , "/" Indicates the meaning of each, "*/5" indicates every five units, "-" indicates that from a number to a number, "," separate several discrete numbers. For specific settings, refer to the/etc/crontab file.
Author William strong