CRONTAB(5) FILE FORMATS CRONTAB(5)
NAME
crontab - table of times to run periodic jobs
SYNOPSIS
/var/spool/cron/crontabs/*
DESCRIPTION
The cron utility is a permanent process, started by
/etc/rc.local. cron consults the files in the directory
/var/spool/cron/crontabs to find out what tasks are to be
done, and at what time.
Each line in a crontab file consists of six fields,
separated by spaces or tabs, as follows:
minutes hours day-of-month month day-of-week command
minutes Minutes field, which can have values in the
range 0 through 59.
hours Hours field, which can have values in the
range 0 through 23.
day-of-month Day of the month, in the range 1 through 31.
month Month of the year, in the range 1 through 12.
day-of-week Day of the week, in the range 0 through 6.
Sunday is day 0 in this scheme of things.
For backward compatibility with older sys-
tems, Sunday may also be specified as day 7.
command Command to be run. A percent character in
this field (unless escaped by \) is
translated to a NEWLINE character. Only the
first line (up to a % or end of line) of the
command field is executed by the Shell. The
other lines are made available to the command
as standard input.
Any of fields 1 through 5 can be a list of values separated
by commas. A value can either be a number, or a pair of
numbers separated by a hyphen, indicating that the job is to
be done for all the times in the specified range. If a
field is an asterisk character (*) it means that the job is
done for all possible values of the field.
Note: the specification of days may be made by two fields
(day of the month and day of the week). If both are speci-
fied as a list of elements, both are adhered to. For exam-
ple,
0 0 1,15 * 1
would run a command on the first and fifteenth of each
month, as well as on every Monday. To specify days by only
one field, the other field should be set to *. For example,
0 0 * * 1
would run a command only on Mondays.
The command is run from your home directory with an arg0 of
sh. Users who desire to have their .profile executed must
explicitly do so in the command. cron supplies a default
environment for every shell, defining HOME, LOGNAME, USER,
SHELL(=/bin/sh), and PATH(=:/usr/ucb:/bin:/usr/bin).
NOTE: Users should remember to redirect the standard output
and standard error of their commands! If this is not done,
any generated output or errors will be mailed to the user.
Lines that start with # are treated as comments.
EXAMPLES
0 0 * * * calendar -
15 0 * * * /usr/etc/sa -s >/dev/null
15 4 * * * find /var/preserve -mtime +7 -a -exec rm -f {} ;
40 4 * * * find / -name '#*' -atime +3 -exec rm -f {} ;
0 0 * * 1-5 /usr/local/weekdays
0 0 * * 0,6 /usr/local/weekends
The calendar command runs at minute 0 of hour 0 (midnight)
of every day. The /usr/etc/sa command runs at 15 minutes
after midnight every day. The two find commands run at 15
minutes past four and at 40 minutes past four, respectively,
every day of the year. The /usr/local/weekdays command is
run at midnight on weekdays. Finally, the
/usr/local/weekends command is run at midnight on weekends.
FILES
/var/spool/cron/crontabs/*
tables of times to run periodic jobs
/etc/rc.local
.profile
SEE ALSO
cron(8), rc(8)
Sun Release 4.1 Last change: 6 October 1988
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