#!/bin/sh

rm -f t.pip t.txt

mkfifo t.pip
printf "line1\nline2\n" >t.txt

ps

{
  while true ; do
    cp t.txt t.pip
  done
} &

rm -f t.rc.*
for rc in 0 1 2 3 4 5 6 7 8 9 ; do
  {
    diff t.pip t.txt
    echo $? >t.rc.$rc
  }
done
echo result1 start
ls  t.rc.* | wc -l
cat t.rc.*
echo result1 end

rm -f t.rc.*
for rc in 0 1 2 3 4 5 6 7 8 9 ; do
  {
    diff t.pip t.txt
    echo $? >t.rc.$rc
  } & # run the readers in parallel
done
sleep 10
echo result2 start
ls  t.rc.* | wc -l
cat t.rc.*
echo result2 end

ps