Spam filter - automatic training

[Whitehill]

According to the doc Mail Service Administration, the system runs every day at 1 am the script /etc/mail/spamassassin/learn_junk_mail to scan mail for users junkmail and notjunkmail. I added the following line at the end of that script

date > /tmp/clammy
​

and then waited until the next morning. No file.

I tried to follow the instructions to the letter. Has anyone else got this to work as advertised?