gistfile1.txt

#!/usr/bin/env bash

mkdir -p foo bar
seq -w 0 100 | xargs -n1 -I{} touch foo/{}.c

echo '["subscribe","./","mysub",{"fields":["name"],"expression":["allof",["type","f"],["not","empty"],["suffix","c"]]}]' | watchman -p -j --server-encoding=json > /dev/null &
while true; do find bar/ -type f | xargs -n1 -P5 -I'{}' mv '{}' foo; done &
while true; do find foo/ -type f | xargs -n1 -P5 -I'{}' mv '{}' bar; done &

wait