CRON(8) UNIX Programmer's Manual CRON(8) NAME cron - clock daemon SYNOPSIS /etc/cron DESCRIPTION _C_r_o_n executes commands at specified dates and times accord- ing to the instructions in the file /_u_s_r/_l_i_b/_c_r_o_n_t_a_b. Since _c_r_o_n never exits, it should only be executed once. This is best done by running _c_r_o_n from the initialization process through the file /etc/rc; see _i_n_i_t(8). Crontab consists of lines of six fields each. The fields are separated by spaces or tabs. The first five are integer patterns to specify the minute (0-59), hour (0-23), day of the month (1-31), month of the year (1-12), and day of the week (1-7 with 1=monday). Each of these patterns may con- tain a number in the range above; two numbers separated by a minus meaning a range inclusive; a list of numbers separated by commas meaning any of the numbers; or an asterisk meaning all legal values. The sixth field is a string that is exe- cuted by the Shell at the specified times. A percent char- acter in this field is translated to a new-line character. Only the first line (up to a % or end of line) of the com- mand field is executed by the Shell. The other lines are made available to the command as standard input. Crontab is examined by _c_r_o_n every minute. FILES /usr/lib/crontab programs for _c_r_o_n to run SEE ALSO sh(1) Printed 5/17/83 1