Python: os.system() redirecting stdout to file in home directory fails

Question

I used the following command :

os.system('scanimage > ~/test.pnm')

but I can't find the image.

Any suggestions?

The > operator always creates a file, even when the command fails (the file is opened before the command is run). After executing os.system(...) you must have test.pnm inside your home directory. It might be empty, but it must be there. If it's not, it means that os.system(...) gets never called. — Andrea Corbellini
– Andrea Corbellini, Commented May 15, 2015 at 11:48
That's exactly the problem, I can't find the file even though the scanner did the scan ! and also when I use a location path (/home/test.pnm) it gives me an error : cannot find /root/home/test.pnm : Directory nonexistance — Ibraheem Darawshi
– Ibraheem Darawshi, Commented May 15, 2015 at 11:58

Mikko Ohtamaa · Accepted Answer · 2015-05-15 12:03:39Z

1

Maybe ~ is not expanded. Try

 os.system("scanimage > $HOME/test.pnm")

and

 os.system("scanimage > /tmp/test.pnm")

Or if you are running as a different UNIX user (root) the home is not what you expect.

answered May 15, 2015 at 12:03

Mikko Ohtamaa

85k63 gold badges296 silver badges479 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Thank you, it seems that ~ was the problem