nohup command &
[root@linuxstudy testshell]# jobs -l
[1]+  2568 Running                 nohup python pytest1.py &
[root@linuxstudy testshell]# bg %1
-bash: bg: job 1 already in background
[root@linuxstudy testshell]# jobs
[1]+  Running                 nohup python pytest1.py &
[root@linuxstudy testshell]# jobs
[1]+  Running                 nohup python pytest1.py &
[root@linuxstudy testshell]# jobs
[1]+  Running                 nohup python pytest1.py &
[root@linuxstudy testshell]# jobs -l
[1]+  2568 Running                 nohup python pytest1.py &
[root@linuxstudy testshell]# nohup python pytest1.py &
[2] 2572
[root@linuxstudy testshell]# nohup: ignoring input and appending output to `nohup.out'
[root@linuxstudy testshell]# jobs -l
[1]-  2568 Running                 nohup python pytest1.py &
[2]+  2572 Running                 nohup python pytest1.py &
[root@linuxstudy testshell]# fg %2
nohup python pytest1.py
fg %1
^C[root@linuxstudy testshell]# jobs -l
[1]+  2568 Running                 nohup python pytest1.py &
[root@linuxstudy testshell]# fg %1
nohup python pytest1.py
^C[root@linuxstudy testshell]#
[root@linuxstudy testshell]# cat pytest1.py 
#!/usr/bin/env python
import os,time
while True:
        print time.time()
        time.sleep(3)
[root@linuxstudy testshell]# cat s3.sh 
#!/bin/sh
echo 'python runs in backend'
python pytest1.py &
[root@linuxstudy testshell]#
root      2588  0.0  0.3 117180  3656 pts/0    S    07:35   0:00 python pytest1.py
root      2614  0.0  0.0 103252   824 pts/1    S+   07:36   0:00 grep py
