====== crontab ======

===== Usage =====


Edit current user's crontab:

  crontab -e
  
List user's crontab:

  crontab -l

Rule, verify website: https://crontab.guru/ :

  0 0 * * * "command"
  

The first five fields shall be integer patterns that specify the following:

  - Minute [0,59]
  - Hour [0,23]
  - Day of the month [1,31]
  - Month of the year [1,12]
  - Day of the week ([0,6] with 0=Sunday)

Symbol:

''*'' (asterisk) means every xxx, for example, ''* * * * *'' means every minutes;

'','' (comma) means **or**, such as ''1,22'' means every 1/22 [classifier];

''-'' (hyphen) means **to**, such as ''1-10'' means from 1 to 10 [classifier];

''*/'' means **every x [classifier]**, ''*/3 [Hour field]'' means every 3 hours.

===== Tips =====

Remember set envirnment at the begining of the code.

<code>
SHELL=/bin/bash
LANG=zh_CN.UTF-8
LC_ALL=zh_CN.UTF-8

0 * * * * /data/backup.sh
</code>