unset HISTORY
echo '' > ~/.bash_history
echo '' > /root/.bash_history
history -c
export HISTSIZE=0
unset HISTFILE

# Shrink the size of log files with `truncate -s 0`
truncate -s 0 /var/log/auth.log
echo '' > /var/log/auth.log
cat /dev/null > /var/log/auth.log
> /var/log/auth.log
dd if=/dev/null of=/var/log/auth.log
shred /var/log/auth.log