exeuting command in background

Question

Hi,

Trying to execute shell command in background using pythons commands module

>>>import commands
>>>output = commands.getstatusoutput("find / > tmp.txt &")
   sh: Syntax error: ";" unexpected

Can anyone explain what is wrong with the syntax ? How should it be executed then ?

Tazim.

Answer 1

I'm not aware of a way to directly execute a command in background like that. Particularly, it's because commands module does not run the command through bash, which is what usually parses the ampersand.

You should do a fork/exec call from the os module to run things in background.

Answer 2

According to the getstatusoutput documentation, commands.getstatusoutput(cmd) is executed as

{ cmd  ; } 2>&1

so your command is run as if it was

{ find / > tmp.txt & ; } 2 >& 1

and the ; is not valid after the & in such a command.

You should use the subprocess module to simulate the old-style os.spawn commands.

Try

subprocess.Popen("find / > tmp.txt", shell=True)

Answer 3

Try to create a daemon to run your process in background.