CRONTAB(8) BSD System Manager's Manual CRONTAB(8) NNAAMMEE ccrroonnttaabb - chronological services schedule file SSYYNNOOPPSSIISS ccrroonnttaabb DDEESSCCRRIIPPTTIIOONN The ccrroonnttaabb file contain the schedules used by the cron(8) daemon. Each line in the schedule gives a time of execution and the command to be exe- cuted. A line consists of two fields giving the time, three fields giving the day, a user name field, and lastly the command to be executed. The first five fields are space or tab separated and may consist of a number, a comma separated list of numbers, or an asterisk meaning any or all possi- ble values. The last field (the command field) may contain spaces. A field containing two hyphen separated numbers is treated as an inclusive range. The fields are: 1. The minute of the hour, a number from 0 to 59. 2. The hour, a number from 0 to 23. 3. The day in terms of the month, a number from 1 to 31. 4. The day in terms of the year, a number from 1 to 12. 5. The day in terms of the week, a number from 1 to 7. Monday is considered day one, Sunday is day seven. 6. The name of a user: the command will be run with the user's uid and permissions. 7. The command to execute. This field may be terminated with a newline of the `%' character. An optional file ccrroonnttaabb..llooccaall may be created and used for addtional scheduling. EEXXAAMMPPLLEESS In the example below, the first field indicates the command should be ex- ecuted at the hour, a quarter past the hour, on the half hour and at a quarter to the hour. The next four fields indicate the command should be run every hour, every day. The sixth field indicates the command is to be run with root privileges. 0,15,30,45 * * * * root /usr/libexec/atrun In this next exmaple, the first field indicates this command should be exectuted on the half hour. The second field constrains the hour to 3 A.M. The third and second fields indicate any day of the month and any day of the year, but are constrained by the fifth field to the sixth day of the week (Saturday). The command is to be executed with root privi- leges. The example shown here has been folded (spread across two lines) to make it readable. It must not be folded in the the ccrroonnttaabb file. 30 3 * * 6 root /bin/sh /etc/weekly 2>&1 | tee /var/log/weekly.out | mail -s "weekly output" root SSEEEE AALLSSOO cron(8) rc(8) FFIILLEESS /etc/crontab General system tasks. /etc/crontab.local Optional local tasks. /etc/rc System initialization script (normally, ccrroonn is exe- cuted from this script.) HHIISSTTOORRYY A ccrroonnttaabb file appeared in Version 6 AT&T UNIX. 4.4BSD June 9, 1993 2