Shell Programming and Scripting

#!/bin/bash
./script1 &
./script2 &
./script3 &
Q=1
 
While (Q==1)
do
PID1=`ps -ef | grep -v grep | grep "script1"`
PID2=`ps -ef | grep -v grep | grep "script2"`
PID3=`ps -ef | grep -v grep | grep "script3"`
 
 
sleep 10 ## you can give here number of seconds as per you wish as not sure about how long scripts wil be taking to complete##
 
if [[ $PID1 == "" && $PID2 == "" && $PID3 == "" ]]
then
       ./script 4
       Q=0
else
       Q=1
fi
done

./script1 &
./script2 &
./script3 &
wait
./script4

wrong=0
./script1 & ./script2 & ./script3 &
for job in $(jobs -p)
do
  wait $job || wrong=$((wrong+1))
done
if [ $wrong = 0 ]; then
  ./script4
fi

( ./script1 ; printf $? > ./script1_ret  )

{
  read rc1 <&3
  read rc2 <&4
  read rc3 <&5
} 3< <(./script1 >/dev/null 2>&1; echo $?) \
  4< <(./script2 >/dev/null 2>&1; echo $?) \
  5< <(./script3 >/dev/null 2>&1; echo $?) 
if [ $rc1 = 0 ] && [ $rc2 = 0 ] && [ $rc3 = 0 ] ; then
  ./script4
fi