periodic.8

Mac OS X 10.4.9 for x86 Source Code crontabs 实现源代码

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.\" $FreeBSD: src/usr.sbin/periodic/periodic.8,v 1.11.2.13 2001/12/14 16:48:11 ru Exp $
.\"
.Dd November 28, 2001
.Os
.Dt PERIODIC 8
.Sh NAME
.Nm periodic
.Nd run periodic system functions
.Sh SYNOPSIS
.Nm
.Ar directory ...
.Sh DESCRIPTION
The
.Nm
program is intended to be called by
.Xr cron 8
to execute shell scripts
located in the specified directory.
.Pp
One or more of the following arguments must be specified:
.Bl -tag -width ".Pa monthly"
.It Pa daily
Perform the standard daily periodic executable run.
This usually occurs early in the morning (local time).
.It Pa weekly
Perform the standard weekly periodic executable run.
This usually occurs on Sunday mornings.
.It Pa monthly
Perform the standard monthly periodic executable run.
This usually occurs on the first day of the month.
.It Ar path
An arbitrary directory containing a set of executables to be run.
.El
.Pp
If an argument is an absolute directory name it is used as is, otherwise
it is searched for under
.Pa /etc/periodic
and any other directories specified by the
.Va local_periodic
setting in
.Xr periodic.conf 5
(see below).
.Pp
The
.Nm
program will run each executable file in the directory or directories
specified.
If a file does not have the executable bit set, it is silently ignored.
.Pp
Each script is required to exit with one of the following values:
.Bl -tag -width 4n
.It 0
The script has produced nothing notable in its output.
The
.Ao Ar basedir Ac Ns Va _show_success
variable controls the masking of this output.
.It 1
The script has produced some notable information in its output.
The
.Ao Ar basedir Ac Ns Va _show_info
variable controls the masking of this output.
.It 2
The script has produced some warnings due to invalid configuration settings.
The
.Ao Ar basedir Ac Ns Va _show_badconfig
variable controls the masking of this output.
.It >2
The script has produced output that must not be masked.
.El
.Pp
If the relevant variable (where
.Aq Ar basedir
is the base directory in which the script resides) is set to
.Dq Li NO
in
.Pa periodic.conf ,
.Nm
will mask the script output.
If the variable is not set to either
.Dq Li YES
or
.Dq Li NO ,
it will be given a default value as described in
.Xr periodic.conf 5 .
.Pp
All remaining script output is delivered based on the value of the
.Ao Ar basedir Ac Ns Va _output
setting.
.Pp
If this is set to a path name (beginning with a
.Ql /
character), output is simply logged to that file.
.Pp
If the
.Ao Ar basedir Ac Ns Va _output
value does not begin with a
.Ql /
and is not empty, it is assumed to contain a list of email addresses, and
the output is mailed to them.
.Pp
If
.Ao Ar basedir Ac Ns Va _output
is not set or is empty, output is sent to standard output.
.Sh ENVIRONMENT
The
.Nm
command sets the
.Ev PATH
environment to include all standard system directories, but no additional
directories, such as
.Pa /usr/local/bin .
If executables are added which depend upon other path components, each
executable must be responsible for configuring its own appropriate environment.
.Sh FILES
.Bl -tag -width ".Pa /etc/periodic.conf"
.It Pa /etc/crontab
The
.Nm
program is typically called via entries in the system default
.Xr cron 8
table.
.It Pa /etc/periodic
The top level directory containing
.Pa daily ,
.Pa weekly ,
and
.Pa monthly
subdirectories which contain standard system periodic executables.
.It Pa /etc/defaults/periodic.conf
The
.Pa periodic.conf
system registry contains variables that control the behaviour of
.Nm
and the standard
.Pa daily , weekly ,
and
.Pa monthly
scripts.
.It Pa /etc/periodic.conf
This file contains local overrides for the default
.Nm
configuration.
.El
.Sh EXAMPLES
The system crontab should have entries for
.Nm
similar to the following example:
.Bd -literal -offset indent
# do daily/weekly/monthly maintenance
0      2       *       *       *       root    periodic daily
0      3       *       *       6       root    periodic weekly
0      5       1       *       *       root    periodic monthly
.Ed
.Pp
The
.Pa /etc/defaults/periodic.conf
system registry will typically have a
.Va local_periodic
variable reading:
.Pp
.Dl local_periodic="/usr/local/etc/periodic /usr/X11R6/etc/periodic"
.Pp
To log
.Nm
output instead of receiving it as email, add the following lines to
.Pa /etc/periodic.conf :
.Bd -literal -offset indent
daily_output=/var/log/daily.log
weekly_output=/var/log/weekly.log
monthly_output=/var/log/monthly.log
.Ed
.Pp
To only see important information from daily periodic jobs, add the
following lines to
.Pa /etc/periodic.conf :
.Bd -literal -offset indent
daily_show_success=NO
daily_show_info=NO
daily_show_badconfig=NO
.Ed
.Sh SEE ALSO
.Xr sh 1 ,
.Xr crontab 5 ,
.Xr periodic.conf 5 ,
.Xr cron 8
.Sh DIAGNOSTICS
Exit status is 0 on success and 1 if the command
fails for one of the following reasons:
.Bl -diag
.It usage: periodic <directory of files to execute>
No directory path argument was passed to
.Nm
to specify where the script fragments reside.
.It <directory> not found
Self explanatory.
.El
.Sh BUGS
Since one specifies information about a directory using shell
variables containing the string,
.Aq Ar basedir ,
.Aq Ar basedir
must only contain characters that are valid within a
.Xr sh 1
variable name, alphanumerics and underscores, and the first character
may not be numeric.
.Sh AUTHORS
.An Paul Traina Aq [e-mail]
.An Brian Somers Aq [e-mail]