Shell script for auditing in Linux

Setup.sh

#!/bin/bash
sudo apt-get install auditd
sudo auditd

#Setting up system parameters
sudo auditctl -b 1000
sudo auditctl -f 1
sudo auditctl -r 5
sudo auditctl -e 1

#Setting up auditing for Files
sudo auditctl -w /etc/shadow
sudo auditctl -w /etc -p wx
sudo auditctl -w /etc/passwd -k fk_passwd -p rwxa



#Setting up for System Call
sudo auditctl -a entry,always -S mkdir
sudo auditctl -a entry,always -S access -F a1=4
sudo auditctl -a exit,always -S ipc -F a0=2

Kindly explain little....