sysctl

# reduce swap usage
https://en.wikipedia.org/wiki/Swappiness
echo "vm.swappiness = 1" > /etc/sysctl.d/90-swap.conf
 
# disable IPv6
echo "net.ipv6.conf.all.disable_ipv6 = 1" > /etc/sysctl.d/01-disable-ipv6.conf
 
# load kernel settings from all system configuration files
sysctl --system
 
# load settings from default configuration /etc/sysctl.conf
sysctl -p
 
# load settings from specified file
sysctl -p /etc/sysctl.d/filename.conf
 
# sysctl
https://www.cyberciti.biz/faq/reload-sysctl-conf-on-linux-using-sysctl/