SYSCTL(8) System Manager's Manual SYSCTL(8) sysctl - sysctl [option ...] variable[=value] ... sysctl -p file-or-regexp ... sysctl /proc/sys/ Linux sysctl procfs sysctl sysctl kernel.ostype "/" "." = = shell -n, --values -e, --ignore -N, --names shell -q, --quiet -w, --write -p[], --load[=] sysctl /etc/sysctl.conf - sysctl -a, --all Display all values currently available except deprecated and verboten parameters. --deprecated --all -b, --binary --system -r, --pattern -A -a -d -h -f -p -X -a -o BSD -x BSD -h, --help -V, --version /proc/sys /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf System file precedence --system sysctl /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf The file /etc/sysctl.conf is read last which means it can replace/override any parameters previously set in files in the listed directories. Deprecated parameters base_reachable_time retrans_time sysctl /proc echo 256 > /proc/sys/net/ipv6/neigh/eth0/base_reachable_time Verboten parameters Certain kernel parameters should not be read due to side-effects and will be skipped by sysctl using the --all option. stat_refresh This parameter returns no value but flushes per-cpu vm statistics. /sbin/sysctl -a /sbin/sysctl -n kernel.hostname /sbin/sysctl -w kernel.domainname="example.com" /sbin/sysctl -p/etc/sysctl.conf /sbin/sysctl -a --pattern forward /sbin/sysctl -a --pattern forward$ /sbin/sysctl -a --pattern 'net.ipv4.conf.(eth|wlan)0.arp' /sbin/sysctl --pattern '^net.ipv6' --system proc(5), sysctl.conf(5), regex(7) Please send bug reports to . procps-ng 2024-07-19 SYSCTL(8)