shell 多进程运行程序

code1

macname@localhost Desktop % 
macname@localhost Desktop % cat test.sh 
#!/bin/bash
echo "Start the test script"
count=1
while [ $count -le 5 ]
do
   echo "Loop #$count"
   sleep 5
   count=$[ $count + 1 ]
done
echo "Test script is complete" 
macname@localhost Desktop % 
macname@localhost Desktop % ./test.sh 
Start the test script
Loop #1
Loop #2
Loop #3
Loop #4
Loop #5
Test script is complete
macname@localhost Desktop % 
macname@localhost Desktop % 

code2

macname@localhost Desktop % 
macname@localhost Desktop % 
macname@localhost Desktop % cat test.sh 
#!/bin/bash
echo "Start the test script"
./a.sh &
./a.sh &
./a.sh &
macname@localhost Desktop % 
macname@localhost Desktop % 
macname@localhost Desktop % cat a.sh 
#!/bin/bash
echo "Start the test script"
count=1
while [ $count -le 5 ]
do
   echo "Loop #$count"
   sleep 5
   count=$[ $count + 1 ]
done
echo "Test script is complete" 
macname@localhost Desktop % 
macname@localhost Desktop % 
macname@localhost Desktop % ./test.sh
Start the test script
macname@localhost Desktop % Start the test script
Loop #1
Start the test script
Loop #1
Start the test script
Loop #1
Loop #2
Loop #2
Loop #2
Loop #3
Loop #3
Loop #3
Loop #4
Loop #4
Loop #4
Loop #5
Loop #5
Loop #5
Test script is complete
Test script is complete
Test script is complete

macname@localhost Desktop % 
macname@localhost Desktop %