1.\"/* Copyright 1988,1990,1993,1994 by Paul Vixie
2.\" * All rights reserved
3.\" *
4.\" * Distribute freely, except: don't remove my name from the source or
5.\" * documentation (don't take credit for my work), mark your changes (don't
6.\" * get me blamed for your possible bugs), don't alter or remove this
7.\" * notice. May be sold if buildable source is provided to buyer. No
8.\" * warrantee of any kind, express or implied, is included with this
9.\" * software; use at your own risk, responsibility for damages (if any) to
10.\" * anyone resulting from the use of this software rests entirely with the
11.\" * user.
12.\" *
13.\" * Send bug reports, bug fixes, enhancements, requests, flames, etc., and
14.\" * I'll try to keep a version up to date. I can be reached as follows:
15.\" * Paul Vixie <paul@vix.com> uunet!decwrl!vixie!paul
16.\" */
17.\"
18.\" $Id$
19.\"
20.TH CRONTAB 5 "24 January 1994"
21.UC 4
22.SH NAME
23crontab \- tables for driving cron
24.SH DESCRIPTION
25A
26.I crontab
27file contains instructions to the
28.IR cron (8)
29daemon of the general form: ``run this command at this time on this date''.
30Each user has their own crontab, and commands in any given crontab will be
31executed as the user who owns the crontab. Uucp and News will usually have
32their own crontabs, eliminating the need for explicitly running
33.IR su (1)
34as part of a cron command.
35.PP
36Blank lines and leading spaces and tabs are ignored. Lines whose first
37non-space character is a pound-sign (#) are comments, and are ignored.
38Note that comments are not allowed on the same line as cron commands, since
39they will be taken to be part of the command. Similarly, comments are not
40allowed on the same line as environment variable settings.
41.PP
42An active line in a crontab will be either an environment setting or a cron
43command. An environment setting is of the form,
44.PP
45 name = value
46.PP
47where the spaces around the equal-sign (=) are optional, and any subsequent
48non-leading spaces in
49.I value
50will be part of the value assigned to
51.IR name .
52The
53.I value
54string may be placed in quotes (single or double, but matching) to preserve
55leading or trailing blanks.
56.PP
57Several environment variables are set up
58automatically by the
59.IR cron (8)
60daemon.
61SHELL is set to /bin/sh, and LOGNAME and HOME are set from the /etc/passwd
62line of the crontab's owner.
63HOME and SHELL may be overridden by settings in the crontab; LOGNAME may not.
64.PP
65(Another note: the LOGNAME variable is sometimes called USER on BSD systems...
66on these systems, USER will be set also.)
67.PP
68In addition to LOGNAME, HOME, and SHELL,
69.IR cron (8)
70will look at MAILTO if it has any reason to send mail as a result of running
71commands in ``this'' crontab. If MAILTO is defined (and non-empty), mail is
72sent to the user so named. If MAILTO is defined but empty (MAILTO=""), no
73mail will be sent. Otherwise mail is sent to the owner of the crontab. This
74option is useful if you decide on /bin/mail instead of /usr/lib/sendmail as
75your mailer when you install cron -- /bin/mail doesn't do aliasing, and UUCP
76usually doesn't read its mail.
77.PP
78The format of a cron command is very much the V7 standard, with a number of
79upward-compatible extensions. Each line has five time and date fields,
80followed by a user name if this is the system crontab file,
81followed by a command. Commands are executed by
82.IR cron (8)
83when the minute, hour, and month of year fields match the current time,
84.I and
85when at least one of the two day fields (day of month, or day of week)
86match the current time (see ``Note'' below).
87.IR cron (8)
88examines cron entries once every minute.
89The time and date fields are:
90.IP
91.ta 1.5i
92field allowed values
93.br
94----- --------------
95.br
96minute 0-59
97.br
98hour 0-23
99.br
100day of month 1-31
101.br
102month 1-12 (or names, see below)
103.br
104day of week 0-7 (0 or 7 is Sun, or use names)
105.br
106.PP
107A field may be an asterisk (*), which always stands for ``first\-last''.
108.PP
109Ranges of numbers are allowed. Ranges are two numbers separated
110with a hyphen. The specified range is inclusive. For example,
1118-11 for an ``hours'' entry specifies execution at hours 8, 9, 10
112and 11.
113.PP
114Lists are allowed. A list is a set of numbers (or ranges)
115separated by commas. Examples: ``1,2,5,9'', ``0-4,8-12''.
116.PP
117Step values can be used in conjunction with ranges. Following
118a range with ``/<number>'' specifies skips of the number's value
119through the range. For example, ``0-23/2'' can be used in the hours
120field to specify command execution every other hour (the alternative
121in the V7 standard is ``0,2,4,6,8,10,12,14,16,18,20,22''). Steps are
122also permitted after an asterisk, so if you want to say ``every two
123hours'', just use ``*/2''.
124.PP
125Names can also be used for the ``month'' and ``day of week''
126fields. Use the first three letters of the particular
127day or month (case doesn't matter). Ranges or
128lists of names are not allowed.
129.PP
130The ``sixth'' field (the rest of the line) specifies the command to be
131run.
132The entire command portion of the line, up to a newline or %
133character, will be executed by /bin/sh or by the shell
134specified in the SHELL variable of the cronfile.
135Percent-signs (%) in the command, unless escaped with backslash
136(\\), will be changed into newline characters, and all data
137after the first % will be sent to the command as standard
138input.
139.PP
140Note: The day of a command's execution can be specified by two
141fields \(em day of month, and day of week. If both fields are
142restricted (ie, aren't *), the command will be run when
143.I either
144field matches the current time. For example,
145.br
146``30 4 1,15 * 5''
147would cause a command to be run at 4:30 am on the 1st and 15th of each
148month, plus every Friday.
149.SH EXAMPLE CRON FILE
150.nf
151
152# use /bin/sh to run commands, no matter what /etc/passwd says
153SHELL=/bin/sh
154# mail any output to `paul', no matter whose crontab this is
155MAILTO=paul
156#
157# run five minutes after midnight, every day
1585 0 * * * $HOME/bin/daily.job >> $HOME/tmp/out 2>&1
159# run at 2:15pm on the first of every month -- output mailed to paul
16015 14 1 * * $HOME/bin/monthly
161# run at 10 pm on weekdays, annoy Joe
1620 22 * * 1-5 mail -s "It's 10pm" joe%Joe,%%Where are your kids?%
16323 0-23/2 * * * echo "run 23 minutes after midn, 2am, 4am ..., everyday"
1645 4 * * sun echo "run at 5 after 4 every sunday"
165.fi
166.SH SEE ALSO
167cron(8), crontab(1)
168.SH EXTENSIONS
169When specifying day of week, both day 0 and day 7 will be considered Sunday.
170BSD and ATT seem to disagree about this.
171.PP
172Lists and ranges are allowed to co-exist in the same field. "1-3,7-9" would
173be rejected by ATT or BSD cron -- they want to see "1-3" or "7,8,9" ONLY.
174.PP
175Ranges can include "steps", so "1-9/2" is the same as "1,3,5,7,9".
176.PP
177Names of months or days of the week can be specified by name.
178.PP
179Environment variables can be set in the crontab. In BSD or ATT, the
180environment handed to child processes is basically the one from /etc/rc.
181.PP
182Command output is mailed to the crontab owner (BSD can't do this), can be
183mailed to a person other than the crontab owner (SysV can't do this), or the
184feature can be turned off and no mail will be sent at all (SysV can't do this
185either).
186.SH AUTHOR
187.nf
188Paul Vixie <paul@vix.com>
2.\" * All rights reserved
3.\" *
4.\" * Distribute freely, except: don't remove my name from the source or
5.\" * documentation (don't take credit for my work), mark your changes (don't
6.\" * get me blamed for your possible bugs), don't alter or remove this
7.\" * notice. May be sold if buildable source is provided to buyer. No
8.\" * warrantee of any kind, express or implied, is included with this
9.\" * software; use at your own risk, responsibility for damages (if any) to
10.\" * anyone resulting from the use of this software rests entirely with the
11.\" * user.
12.\" *
13.\" * Send bug reports, bug fixes, enhancements, requests, flames, etc., and
14.\" * I'll try to keep a version up to date. I can be reached as follows:
15.\" * Paul Vixie <paul@vix.com> uunet!decwrl!vixie!paul
16.\" */
17.\"
18.\" $Id$
19.\"
20.TH CRONTAB 5 "24 January 1994"
21.UC 4
22.SH NAME
23crontab \- tables for driving cron
24.SH DESCRIPTION
25A
26.I crontab
27file contains instructions to the
28.IR cron (8)
29daemon of the general form: ``run this command at this time on this date''.
30Each user has their own crontab, and commands in any given crontab will be
31executed as the user who owns the crontab. Uucp and News will usually have
32their own crontabs, eliminating the need for explicitly running
33.IR su (1)
34as part of a cron command.
35.PP
36Blank lines and leading spaces and tabs are ignored. Lines whose first
37non-space character is a pound-sign (#) are comments, and are ignored.
38Note that comments are not allowed on the same line as cron commands, since
39they will be taken to be part of the command. Similarly, comments are not
40allowed on the same line as environment variable settings.
41.PP
42An active line in a crontab will be either an environment setting or a cron
43command. An environment setting is of the form,
44.PP
45 name = value
46.PP
47where the spaces around the equal-sign (=) are optional, and any subsequent
48non-leading spaces in
49.I value
50will be part of the value assigned to
51.IR name .
52The
53.I value
54string may be placed in quotes (single or double, but matching) to preserve
55leading or trailing blanks.
56.PP
57Several environment variables are set up
58automatically by the
59.IR cron (8)
60daemon.
61SHELL is set to /bin/sh, and LOGNAME and HOME are set from the /etc/passwd
62line of the crontab's owner.
63HOME and SHELL may be overridden by settings in the crontab; LOGNAME may not.
64.PP
65(Another note: the LOGNAME variable is sometimes called USER on BSD systems...
66on these systems, USER will be set also.)
67.PP
68In addition to LOGNAME, HOME, and SHELL,
69.IR cron (8)
70will look at MAILTO if it has any reason to send mail as a result of running
71commands in ``this'' crontab. If MAILTO is defined (and non-empty), mail is
72sent to the user so named. If MAILTO is defined but empty (MAILTO=""), no
73mail will be sent. Otherwise mail is sent to the owner of the crontab. This
74option is useful if you decide on /bin/mail instead of /usr/lib/sendmail as
75your mailer when you install cron -- /bin/mail doesn't do aliasing, and UUCP
76usually doesn't read its mail.
77.PP
78The format of a cron command is very much the V7 standard, with a number of
79upward-compatible extensions. Each line has five time and date fields,
80followed by a user name if this is the system crontab file,
81followed by a command. Commands are executed by
82.IR cron (8)
83when the minute, hour, and month of year fields match the current time,
84.I and
85when at least one of the two day fields (day of month, or day of week)
86match the current time (see ``Note'' below).
87.IR cron (8)
88examines cron entries once every minute.
89The time and date fields are:
90.IP
91.ta 1.5i
92field allowed values
93.br
94----- --------------
95.br
96minute 0-59
97.br
98hour 0-23
99.br
100day of month 1-31
101.br
102month 1-12 (or names, see below)
103.br
104day of week 0-7 (0 or 7 is Sun, or use names)
105.br
106.PP
107A field may be an asterisk (*), which always stands for ``first\-last''.
108.PP
109Ranges of numbers are allowed. Ranges are two numbers separated
110with a hyphen. The specified range is inclusive. For example,
1118-11 for an ``hours'' entry specifies execution at hours 8, 9, 10
112and 11.
113.PP
114Lists are allowed. A list is a set of numbers (or ranges)
115separated by commas. Examples: ``1,2,5,9'', ``0-4,8-12''.
116.PP
117Step values can be used in conjunction with ranges. Following
118a range with ``/<number>'' specifies skips of the number's value
119through the range. For example, ``0-23/2'' can be used in the hours
120field to specify command execution every other hour (the alternative
121in the V7 standard is ``0,2,4,6,8,10,12,14,16,18,20,22''). Steps are
122also permitted after an asterisk, so if you want to say ``every two
123hours'', just use ``*/2''.
124.PP
125Names can also be used for the ``month'' and ``day of week''
126fields. Use the first three letters of the particular
127day or month (case doesn't matter). Ranges or
128lists of names are not allowed.
129.PP
130The ``sixth'' field (the rest of the line) specifies the command to be
131run.
132The entire command portion of the line, up to a newline or %
133character, will be executed by /bin/sh or by the shell
134specified in the SHELL variable of the cronfile.
135Percent-signs (%) in the command, unless escaped with backslash
136(\\), will be changed into newline characters, and all data
137after the first % will be sent to the command as standard
138input.
139.PP
140Note: The day of a command's execution can be specified by two
141fields \(em day of month, and day of week. If both fields are
142restricted (ie, aren't *), the command will be run when
143.I either
144field matches the current time. For example,
145.br
146``30 4 1,15 * 5''
147would cause a command to be run at 4:30 am on the 1st and 15th of each
148month, plus every Friday.
149.SH EXAMPLE CRON FILE
150.nf
151
152# use /bin/sh to run commands, no matter what /etc/passwd says
153SHELL=/bin/sh
154# mail any output to `paul', no matter whose crontab this is
155MAILTO=paul
156#
157# run five minutes after midnight, every day
1585 0 * * * $HOME/bin/daily.job >> $HOME/tmp/out 2>&1
159# run at 2:15pm on the first of every month -- output mailed to paul
16015 14 1 * * $HOME/bin/monthly
161# run at 10 pm on weekdays, annoy Joe
1620 22 * * 1-5 mail -s "It's 10pm" joe%Joe,%%Where are your kids?%
16323 0-23/2 * * * echo "run 23 minutes after midn, 2am, 4am ..., everyday"
1645 4 * * sun echo "run at 5 after 4 every sunday"
165.fi
166.SH SEE ALSO
167cron(8), crontab(1)
168.SH EXTENSIONS
169When specifying day of week, both day 0 and day 7 will be considered Sunday.
170BSD and ATT seem to disagree about this.
171.PP
172Lists and ranges are allowed to co-exist in the same field. "1-3,7-9" would
173be rejected by ATT or BSD cron -- they want to see "1-3" or "7,8,9" ONLY.
174.PP
175Ranges can include "steps", so "1-9/2" is the same as "1,3,5,7,9".
176.PP
177Names of months or days of the week can be specified by name.
178.PP
179Environment variables can be set in the crontab. In BSD or ATT, the
180environment handed to child processes is basically the one from /etc/rc.
181.PP
182Command output is mailed to the crontab owner (BSD can't do this), can be
183mailed to a person other than the crontab owner (SysV can't do this), or the
184feature can be turned off and no mail will be sent at all (SysV can't do this
185either).
186.SH AUTHOR
187.nf
188Paul Vixie <paul@vix.com>