python subprocess.check_output giving wrong output -

i have problem execute code here

subprocess.check_output(['ps -ef | grep ftp | wc -l'],env=environ,shell=true) 

when execute terminal

ps -ef | grep ftp | wc -l 

i "1" output fine.

now, execute same code python files subprocess.check_output , gives me 2. strange. ideas why happening. here complete code:

 def countfunction():     environ = dict(os.environ)     return subprocess.check_output(['ps -ef | grep ftp | wc -l'],env=environ,shell=true)   count = countfunction()       print count 

edit: update , not have ftp connections on.so command line printing 1 on command fine. arvind

the grep command find itself:

$ ps -ef | grep ftp wallyk  12546 12326  0 16:25 pts/3    00:00:00 grep ftp 

if don't want that, exclude grep command:

$ ps -ef | grep ftp | grep -v ftp $ 

it better drop -f switch ps command line arguments not searched. way, won't find grep ftp running:

$ ps -e | grep ftp | wc -l