CRON(8) UNIX Programmer's Manual CRON(8) NAME cron - clock daemon SYNOPSIS /usr/sbin/cron DESCRIPTION Cron executes commands at specified dates and times accord- ing to the instructions in the file /etc/crontab (if it exists). Since cron never exits, it should only be executed once. This is best done by running cron from the initialization process through the file /etc/inittab; see init(8). The crontab file consists of lines of seven fields each. The fields are separated by spaces or tabs. The first five are integer patterns to specify: o+ minute (0-59) o+ hour (0-23) o+ day of the month (1-31) o+ month of the year (1-12) o+ day of the week (1-7 with 1 = Monday) Each of these patterns may contain: o+ a number in the range above o+ two numbers separated by a minus meaning a range inclusive o+ a list of numbers separated by commas meaning any of the numbers o+ an asterisk meaning all legal values The sixth field is a user name: the command will be run with that user's uid and permissions. The seventh field consists of all the text on a line following the sixth field, includ- ing spaces and tabs; this text is treated as a command which is executed by the Shell at the specified times. A percent character (``%'') in this field is translated to a new-line character. The crontab file is checked by cron every minute, on the minute. FILES /etc/crontab