bash done 53 lines

src/bash.sh

@@ -0,0 +1,63 @@
+#! /bin/bash
+
+main() {
+   set -e
+   set -o pipefail
+
+   cleanup() {
+      if jobs -p | grep -q .; then
+         kill -9 $(jobs -p) &> /dev/null
+      fi
+   }
+   trap cleanup EXIT
+
+   export _D="$(mktemp -d)"
+   export _P=3
+   export _N=100
+
+   for i in $(seq 0 $((_P-1))); do
+      mkfifo "$_D/pipe.$i"
+   done
+
+   scatter
+   gather
+
+   rm -rf "$_D"
+}
+
+scatter() {
+   for i in $(seq 0 $((_P-1))); do
+      _scatter $i &
+   done
+}
+
+_scatter() {
+   local i="$1"
+   local chunk=$((_N/_P))
+   local start=$((chunk*i))
+   if ((i==_P-1)); then
+      chunk=$((chunk+_N%_P))
+   fi
+   local result=0
+   for j in $(seq $start $((start+chunk))); do
+      ((result+=j)) || true
+   done
+   echo "> _scatter $i processing $start..$((start+chunk)) found $result" >&2
+   echo $result > "$_D/pipe.$i"
+}
+
+gather() {
+   echo "> gather..." >&2
+   local ttl=0
+   for f in "$_D"/pipe.*; do
+      echo "> cat $f" >&2
+      ttl=$((ttl+$(timeout 1 cat "$f" || echo 0)))
+   done
+   echo "> wait" >&2
+   wait
+   echo "> /gather $ttl" >&2
+}
+
+if [ "$0" == "$BASH_SOURCE" ]; then
+   main "$@"
+fi