Open System Services Management and Operations Guide (G06.25+, H06.03+)

Operating the OSS Environment
Open System Services Management and Operations Guide—527191-002
2-35
Using the cron Process
product with the TACL OSH command. The following subsections discuss these
options:
•
Using the cron Process on page 2-35
•
Using the NetBatch Product on page 2-38
Using the cron Process
The cron process runs shell commands at specified dates and times. The commands
that are to be run and the schedule are placed in entries within files in a specific
directory. Commands that are to run only once are placed within files in the at queue.
Commands that can be run at system-determined times are placed within files in the
batch queue.
The cron process supports the following OSS shell commands:
•
The crontab Command on page 2-36
•
The at Command on page 2-37
•
The atq Command on page 2-37
•
The atrm Command on page 2-38
•
The batch Command on page 2-38
Because the cron process exits only when killed or when the system stops, only one
cron process should exist on the system at any given time. You can ensure that only
one process runs by using the CRON_NAMED environment variable before starting any
copy of cron; always use the same process name.
For more information about starting and managing the cron process, see the
cron(8) reference page either online or in the Open System Services Shell and
Utilities Reference Manual.
Configuring the cron Process
You must create the following files to configure the cron process. The cron process
uses these files to determine whether and when to run shell commands:
/usr/lib/cron/at.deny Lists the user IDs that are denied
access to the at queue
/var/spool/cron/crontabs/crontab Lists the commands to be run at
specified times.
/var/adm/cron/cron.allow Lists the user IDs that are allowed
to change the crontab file. (This
file is optional; see the
crontab(1) reference page
either online or in the Open
System Services Shell and Utilities
Reference Manual for more
information.)