python - Why are os.system and subprocess.call spawning so many processes? -

import os import subprocess import sys import re  ## fname_ext=sys.argv[1] fname_ext=r"c:\mine\.cs\test.cs" exe=os.path.splitext(fname_ext)[0]+".exe" # executable fdir=os.path.split(fname_ext)[0] fcontent=open(fname_ext).read()  p_using=re.compile("\s*using\s+((\w+[.]*)+)") p_namespace=re.compile("\s*namespace\s+(\w+)") usings=p_using.findall(fcontent) usings=[x[0] x in usings] references=[] in os.listdir(fdir):     path=fdir+"\\"+i     try:         if os.path.isdir(path) or (not path.endswith('cs')):continue         open(path) fp:             content=fp.read()             namespaces=p_namespace.findall(content)             n in namespaces:                 if n in usings , 'system' not in n:                     references+=[path]     except:         pass  command="csc /nologo "+" ".join(references)+" "+fname_ext ## command=" ".join(references) #~ --------------------------------------------------------- # build: option=1 if option==0:     # using os.system     print ">>",command     if os.system(command)==0:         os.system(exe) else:     #~ using subprocess module     ## print type(references)     command=['csc']     ## print command,references     command.extend(["/nologo","/out:"+exe])     command.extend(references)     command.append(fname_ext)     ## print command     if subprocess.call(command,shell=true)==0:         ## print "running %s"%exe         subprocess.call([exe],shell=true)     else:         pass         ## print "failed run" #~ --------------------------------------------------------- 

i have code above supposed run csharp program scite. searches
every .cs file in directory , finds file namespace current
file has included. command run file in scite is:
command.go.*.cs=python c:\mine\.py\csc.py $(filepath)
command.go.subsystem.*.cs=0

that program logic part okay.
issue when hit f5 sample csharp code this:

using system; using system.collections; using mynamespace; class test{     public static void main(string[] args){         myobject inst=new myobject();         myobject.self_destruct(inst);     } } 

it runs ok. when uncomment second fname_ext , comment first one
, run csc.py file, window opens , keeps running, printing command(this happens
using os.system option). when use the subprocess.call option, same thing
happens time when shell=true. ran 15 seconds , there 800+ cmd.exe , python.exe processes.i had wait 5 minutes after killing cmd.exe
mouse start responding , 2 minutes more desktop peek work.
when shell=false, runs ok, same way when hit f5 key file.
what happening here?
what shell=true doing makes behave way?

okay, i'll take stab @ this. if understand situation, script called csc.py , want call csc c# compiler. when run csc /nologo (etc...) through cmd.exe, starts looking called 'csc' known extension. finds csc.py in current directory , since .py registered extension, that's gets executed.

the solution rename python file or call out 'csc.exe' explicitly.