Administering user accounts

Controlling the use of job scheduling commands

You can control use of the cron(C), at(C), and batch(C) commands that schedule or delay the execution of processes. Use the Cron Manager located in the System directory of the SCOadmin hierarchy.

The Cron Manager performs these tasks:

NOTE: In addition to granting permission to use these commands, you must make sure that the users have the chmodsugid privilege.

Changing the default permissions for job scheduling

The system is initially configured to permit use of the job scheduling commands by root, sys, adm and uucp only, denying access to other users.

To change the system defaults, make these selections in the Cron Manager (the first is for cron and the second for at and batch):

Authorize Scheduled Default
Authorize Delayed Default

These three selections are displayed:

None: Execution is not permitted for any users.
Allow: Allow all users to execute the command.
Deny: Deny all users access to the command.

The current behavior is highlighted. Use the arrow keys to select the behavior desired, or enter the first letter. Remember that users can be allowed or denied on an individual basis as well. The settings for individuals take precedence over the system defaults.

Changing the job scheduling permissions for a user

To change individual user permissions, make these selections in the Cron Manager (the first is for cron and the second for at and batch):

Authorize Scheduled User
Authorize Delayed User

The cursor is placed on the ``User:'' field. Enter the name of the user or press <F3> for a list of possible users. When the user name is selected, these selections are displayed:

Allow: Allow this user to execute the command.
Deny: Deny this user access to the command.

Use the arrow keys to select the behavior required. This setting overrides the system default.

Using environment files for the at or batch commands

It is also possible to define the environment in which at and batch commands execute. To edit the at and batch prototype files respectively, use these selections in the Cron Manager:

Authorize Environment At
Authorize Environment Batch

NOTE: Only root can make these selections.

These options edit the files /usr/lib/cron/.proto (for at) or /usr/lib/cron/.proto.b (for batch). These files are placed at the start of the shell script formed for all at and batch jobs. This script must conform to the usual /bin/sh syntax and contain some variables particular to the prototype file. These variables are:

$d: Current directory of the user at the time of submission.
$l: ulimit for the user at the time of submission.
$m: umask for the user at the time of submission.
$t: Time (in seconds past 1 Jan 1970) that the script is run.
$<: Replaced with the entire script that the user submits. Normally, this appears last in the file, after the prologue that you set up. If you decide to include information after this variable, the shell script may exit before reaching it.

Only the superuser can edit these files.

Example environment files

There are many uses for prototype files; two examples are shown below:

Run jobs in a particular queue at a lower priority by inserting a nice(C) command:
```
   nice -5 /bin/sh << 'END_OF_FILE'
   $<
   END_OF_FILE
```
Specify that a queue should execute commands using an alternative shell:
```
   /bin/csh << 'END_OF_FILE'
   $<
   END_OF_FILE
```

For most sites, the prototype files provided with the distribution should be sufficient.