Basic rice set up. Still need to add a way to reiably update the package lists and i need a launcher.

private_dot_local/bin/executable_cpucore

@@ -0,0 +1,99 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# elevate once, then never again
+if (( EUID != 0 )); then
+  exec sudo -p "Password: " "$0" "$@"
+fi
+
+PROG=$(basename "$0")
+
+usage() {
+  cat <<EOF
+Usage: $PROG N|--reset
+  N        Number of logical CPUs to keep online (integer >= 1)
+  --reset  Bring all logical CPUs online
+EOF
+  exit 1
+}
+
+get_total_cpus() { nproc --all; }
+
+set_cpu_online() {
+  local cpu=$1 val=$2
+  local f="/sys/devices/system/cpu/cpu${cpu}/online"
+  [[ -e $f ]] || return 0
+  local cur
+  cur=$(cat "$f" 2>/dev/null || echo "")
+  [[ $cur == "$val" ]] && return 0
+  printf '%s\n' "$val" >"$f" 2>/dev/null || \
+    echo "Warning: failed to set cpu${cpu} online=$val" >&2
+}
+
+reset_cpus() {
+  local total=$1
+  for ((i = 0; i < total; i++)); do
+    set_cpu_online "$i" 1
+  done
+}
+
+apply_target() {
+  local target=$1 total=$2
+  for ((i = 0; i < total; i++)); do
+    if ((i < target)); then
+      set_cpu_online "$i" 1
+    elif ((i > 0)); then
+      set_cpu_online "$i" 0
+    fi
+  done
+}
+
+list_online() {
+  local total=$1
+  local online=()
+  for ((i = 0; i < total; i++)); do
+    local f="/sys/devices/system/cpu/cpu${i}/online"
+    if [[ -e $f ]]; then
+      [[ $(cat "$f") == 1 ]] && online+=("$i")
+    else
+      online+=("$i")
+    fi
+  done
+  echo "Online CPUs: ${online[*]}"
+}
+
+main() {
+  local total
+  total=$(get_total_cpus)
+
+  if [[ $# -ne 1 ]]; then
+    usage
+  fi
+
+  case $1 in
+    --reset)
+      reset_cpus "$total"
+      echo "Done."
+      ;;
+    [0-9]*)
+      local target=$1
+      if ((target <= 0)); then
+        echo "Warning: minimum of 1 CPU required; using 1." >&2
+        target=1
+      fi
+      if ((target >= total)); then
+        reset_cpus "$total"
+        echo "Done."
+      else
+        apply_target "$target" "$total"
+        list_online "$total"
+      fi
+      ;;
+    *)
+      usage
+      ;;
+  esac
+}
+
+main "$@"
+