CRONTAB(1) DOMAIN/IX Reference Manual (SYS5) CRONTAB(1)
NAME
crontab - make a user crontab file
USAGE
crontab option
crontab [file]
DESCRIPTION
Crontab copies the specified file (or the standard input if
no file is named), into a directory that holds all users'
crontab files.
You can use crontab if your name appears in the file
/usr/lib/cron/cron.allow. If that file does not exist, the
file /usr/lib/cron/cron.deny determines whether you are
allowed to use cron. If /usr/lib/cron/cron.allow does not
exist and /usr/lib/cron/cron.deny is empty, global use is
allowed. If neither file exists, only root can submit a
job. The allow/deny files consist of one user name per
line.
OPTIONS
Crontab recognized the following options:
-l List the current user's crontab file.
-r Remove the current user's crontab file.
CRONTAB FILE FORMAT
A crontab file consists of lines of six fields each. The
fields are separated by spaces or tabs. The first five are
integer patterns that specify the following information:
minute (0-59)
hour (0-23)
day of month (1-31)
month of year (1-12)
day of week (0-6, 0=Sunday)
Each of these patterns may be either an asterisk (*) to sig-
nify all legal values, or a list of elements separated by
commas. An element is either a number, or two numbers
separated by a dash (-) to indicate an inclusive range.
Note that you can specify days by using day of the month
and/or day of the week. If you use both fields as a list of
elements, both are adhered to. For example,
0 0 1,15 * 1 command
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CRONTAB(1) DOMAIN/IX Reference Manual (SYS5) CRONTAB(1)
runs command on the first and fifteenth of each month, as
well as on every Monday. To specify the days in a single
field, the other field should be set to an asterisk (*). For
example:
0 0 * * 1 command
runs command only on Mondays.
The sixth field of a line in a crontab file is a string that
is executed by the shell at the specified times. A percent
character (%) in this field, unless escaped by a backslash
(\) is translated to a newline character. Only the first
line of the command field, up to a percent (%) or end of
line, is executed by the Shell. The other lines are made
available to the command as standard input.
Cron invokes the shell from your $HOME directory with an
arg0 of sh (1). Your .profile will not be executed unless
you make an explicit request in the crontab file. The cron
(1M) command supplies a default environment for every Shell,
defining HOME, LOGNAME, SHELL (=/bin/sh), and PATH
(=:/bin:/usr/bin:/usr/lbin).
EXAMPLES
The first line below installs the file /tmp/ct as your cron-
tab. The second line lists that file.
# crontab /tmp/ct
# crontab -l
00 * * * * echo `date` >>/tmp/cron
The crontab file listed above writes the date into a file
once every hour.
CAUTIONS
If you do not redirect standard output and standard error
when using crontab, any generated output or errors are
mailed to you.
FILES
/usr/lib/cron main cron directory (link to `node_data/cron)
/usr/spool/cron/crontabs
spool area
/usr/lib/cron/log
accounting information
/usr/lib/cron/cron.allow
list of allowed users
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CRONTAB(1) DOMAIN/IX Reference Manual (SYS5) CRONTAB(1)
/usr/lib/cron/cron.deny
list of denied users
RELATED INFORMATION
sh (1), cron (1M).
Printed 1/29/86 CRONTAB-3