Linux SysRq examples

forcero.sh

#!/bin/sh

# Remount all filesystems read-only

echo "sync disks."
echo s > /proc/sysrq-trigger

sleep 2

echo "remount all read-only."
echo u > /proc/sysrq-trigger

sysrq.sh

#!/bin/bash

options=()

options[0]="disable every SysRq function."
options[1]="enable every SysRq function."
options[2]="enable control of console logging level"
options[4]="enable control of keyboard (SAK, unraw)"
options[8]="enable debugging dumps of processes etc."
options[16]="enable sync command"
options[32]="enable remount read-only"
options[64]="enable signalling of processes (term, kill, oom-kill)"
options[128]="allow reboot/poweroff"
options[256]="allow nicing of all RT tasks"

echo "Enabled SysRq options:"

for i in $(seq 1 8); do 
        (( ($(</proc/sys/kernel/sysrq) & $((1<<$i))) > 0 )) && echo -e "$((1<<$i))\t${options[$((1<<$i))]}"
done