os.system()

[rami823]

Hi,
I am tryting to invoke an application that is located at:
"P:\P_NS0\tools \tpprogV27k.exe "

I am only using the following the following code:

import os
os.system("P:\P _NS0\tools\tppr ogV27k.exe");

I get the following error:
'P:\P_NS0' is not recognized as an internal or external command,
operable program or batch file.

If I type the same code in PythonWin I get the following:

>>> os.system("P:\P _NS0\tools\tppr ogV27k.exe");
1

Please help me I am a new pyhton user any help is greatly appreciated.

[boxfish]

Hi,
Do you know about escape sequences? If a character in a string has a backslash in front of it, it and the backslash are treated as one special character. I think this may be the source of your problem. If you put two backslashes in a row, they are treated as a single backslash. Try that and see if it helps.
Good luck.

[rami823]

Hi,
Do you know about escape sequences? If a character in a string has a backslash in front of it, it and the backslash are treated as one special character. I think this may be the source of your problem. If you put two backslashes in a row, they are treated as a single backslash. Try that and see if it helps.
Good luck.

Thanks for the help,
I tried the following and I got these:


>>> os.system("c:/")
1
>>> os.system("c:/")
1
>>> os.system("P:/")
1
>>> os.system("c:")
0
>>> os.system("P:")

but neither C: nor P: drive opened

[boxfish]

If you're using windows, and you want to open those drives with Windows Explorer, use the explorer command:

os.system("explorer \"c:\\\")

(the backslashes before the quotes differentiate them from the end of the string).

If you want to change the active directory to one of those drives, use the chdir function:

os.chdir("c:\\")

Or are you trying to do something else?

[shreyask]

have you tried this -

>>os.system(r"P:\P_NS0\tools \tpprogV27k.exe ");

in case you missed the change, there is an extra 'r' (meaning raw), before specifying the string.

-
shreyas

[rami823]

have you tried this -

>>os.system(r"P:\P_NS0\tools \tpprogV27k.exe ");

in case you missed the change, there is an extra 'r' (meaning raw), before specifying the string.

-
shreyas

Thank you shreyas it worked :)

[rami823]

Thank you shreyas it worked :)

hi,
I have now another problem,
I am opening two programs using two

os.system() commands but the problem is that the second program does not open unless I close the first one.
It does not matter which program comes first

thank you all for the support
Ram

[Laharl]

Right. System() does not return to Python until after the program run with it exits. If you want it to run separately, look up the os.exec family of functions after creating a separate process with os.fork().

Documentation for both can be found on the Internet, but will most likely refer to the C versions these are wrappers for.

[rami823]

Right. System() does not return to Python until after the program run with it exits. If you want it to run separately, look up the os.exec family of functions after creating a separate process with os.fork().

Documentation for both can be found on the Internet, but will most likely refer to the C versions these are wrappers for.

I learned from little research that the function os.fork() does not work on microsoft windows and it only works on linux.

[Laharl]

That is likely because the C version is a *nix system call...I figured the Python guys would have set up a wrapper to a similar Windows system call, CreateProcess. You've reached the end of my knowledge of Windows-specific Python, I'm afraid...