#!/bin/bash# background-loop.shfor i in 1 2 3 4 5 6 7 8 9 10            # First loop.do  echo -n "$i "done & # Run this loop in background.       # Will sometimes execute after second loop.echo   # This 'echo' sometimes will not display.for i in 11 12 13 14 15 16 17 18 19 20   # Second loop.do  echo -n "$i "done  echo   # This 'echo' sometimes will not display.# ======================================================# The expected output from the script:# 1 2 3 4 5 6 7 8 9 10 # 11 12 13 14 15 16 17 18 19 20 # Sometimes, though, you get:# 11 12 13 14 15 16 17 18 19 20 # 1 2 3 4 5 6 7 8 9 10 bozo $# (The second 'echo' doesn't execute. Why?)# Occasionally also:# 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20# (The first 'echo' doesn't execute. Why?)# Very rarely something like:# 11 12 13 1 2 3 4 5 6 7 8 9 10 14 15 16 17 18 19 20 # The foreground loop preempts the background one.exit 0#  Nasimuddin Ansari suggests adding    sleep 1#+ after the   echo -n "$i"   in lines 6 and 14,#+ for some real fun.