32v 1m cron
From Computer History Wiki
CRON(1M) UNIX Programmer's Manual CRON(1M)
cron - clock daemon
_C_r_o_n executes commands at specified dates and times accord- ing to the instructions in the file /usr/lib/crontab. 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.