/usr/sbin/amavisd-new-cronjob is in amavisd-new 1:2.10.1-2ubuntu1.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 | #!/bin/bash
# amavisd-new cronjob helper
#
# Run it as the amavis user
#
# First parameter specifies which cronjob routine to run:
# 		sa-sync:	spamassassin fast sync
# 		sa-clean:	spamassassin cleanup
test -e /usr/bin/sa-learn || exit 0
test -e /usr/sbin/amavisd-new || exit 0
if [ "$(id --name -u)" != "amavis" ]
then
    echo "Please run this cronjob as user amavis"
    exit 1
fi
set -e
umask 022
if ! perl -MMail::SpamAssassin -e "my \$spamtest = Mail::SpamAssassin->new();
\$spamtest->compile_now (); \$spamtest->{conf}->{use_bayes} ? exit 0 : exit 1"
then
	#bayes is disabled - just exit
	exit
fi
case $1 in
	sa-sync)
		/usr/bin/sa-learn --sync 2>&1 >/dev/null
		;;
	sa-clean)
		/usr/bin/sa-learn --sync --force-expire 2>&1 >/dev/null
		;;
	*)
		echo "$0: unknown cron routine $1" >&2
		exit 1
		;;
esac
exit 0
 |