Open System Services Shell and Utilities Reference Manual (G06.29+, H06.08+, J06.03+)

Administrator Commands and Files cron(8)
NAME
cron - Runs the system clock daemon
SYNOPSIS
cron [ -f ]
FLAGS
-f Run the cron process in the foreground.
This flag is valid for systems running:
• J06.05 and later J-series RVUs
• H06.16 and later H-series RVUs
• G06.33 and later G-series RVUs
• J06.03, J06.04, or H06.03 through H06.15 RVUs and have installed SPR
T8626H03ˆACU
• G06.29 through G06.32 RVUs and have installed SPR T8626G07ˆACV
DESCRIPTION
The cron daemon runs shell commands at specified dates and times. Because the cron process
exits only when killed or when the system stops, only one cron daemon should exist on the sys-
tem at any given time.
In systems that support the -f flag, you can start the cron process as a persistent generic process.
Add the cron process to $ZZKRN and associate it with the OSH process. Configure the cron
process as follows:
• Set the STARTUPMSG attribute to:
"-osstty -name /G/process_name -p /bin/cron -f"
where process_name is a Guardian process name of the persistent cron process.
• Set the ASSOCPROC attribute to the same name as you used for the persistent cron pro-
cess in the STARTUPMSG attribute.
• The attibutes HOMETERM, INFILE, and OUTFILE are required.
For information about the rules that apply to the Guardian process name, see "Environment Vari-
ables." For an example of adding the cron process as a persistent process, see "Examples." For
information about configuring a generic process, see the SCF Reference Manual for the Kernel
Subsystem.
Commands that are to run according to a regular or periodic schedule are found within the cron-
tab files. Commands that are to run only once are found within the at files. You submit crontab
and at file entries by using the crontab and at commands.
During process initialization and when cron detects a change, it examines the crontab and at
files. This strategy reduces the overhead of checking for new or changed files at regularly
scheduled intervals.
The cron command creates a log of its activities as a file named log in the directory
/var/adm/cron. When the log file size exceeds 2.5 MB (2,621,440 bytes), the log file is closed
and renamed to save its information. A new log file named log is created in the same directory.
The renamed log file’s filename has the format
log_yyyymmddhhnnss
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