Customizing the cron daemon for the first time

If you are customizing for the first time, you will have to perform some setup steps. The steps assume that /usr/spool and /usr/lib/cron do not exist or that they are empty directories. If these assumptions are not true, then you need to follow the instructions in Migrating from a previous release.

Set up an /etc/spool (or /var/spool) directory. Consider using /var/spool rather than /etc/spool and using a separate file system for the cron spool data.
Tip: The /var directory is the location for IBM® products to put their own customization and execution data. It is for IBM product usage only and cannot be edited or modified by you. It is up to you to decide where to put the spool directory. However, because those files are built by cron when it runs, they are suitable for the /var directory. In addition, because /etc typically contains a lot of data and /var does not, using /var might keep /etc from being overloaded.
1. Create the /etc/spool directory and set its permissions to 755.
  Example:
```
mkdir -m 755 /etc/spool
chmod 755 /etc/spool
```
2. Remove the empty /usr/spool directory, if it exists.
  Example:
```
rmdir /usr/spool
```
3. Create a symbolic link from /usr/spool to /etc/spool.
  Example:
```
ln -s /etc/spool /usr/spool
```
Set up an /etc/cron directory.
1. Create the /etc/cron directory and set its permissions to 755.
  Example:
```
mkdir -m 755 /etc/cron
chmod 755 /etc/cron
```
2. Remove the empty /usr/lib/cron directory, if it exists.
  Example:
```
rmdir /usr/lib/cron 
```
3. Create a symbolic link from /usr/lib/cron to /etc/cron.
  Example:
```
ln -s /etc/cron /usr/lib/cron
```

Create the /etc/spool/cron, /etc/spool/cron/atjobs and /etc/spool/cron/crontabs directories and set their permissions to 755.

Example:

mkdir -m 755 /etc/spool/cron
chmod 755 /etc/spool/cron

mkdir -m 755 /etc/spool/cron/atjobs
chmod 755 /etc/spool/cron/atjobs

mkdir -m 755 /etc/spool/cron/crontabs
chmod 755 /etc/spool/cron/crontabs

When you are done, you have customized the cron daemon for the first time.