[Tutor] help with running perl script that writes to a text file

[Peter Otten]

3n2 Solutions wrote:

> Hello,
> 
> I want to automate the following manual process from DOS promp:
> 
> c:/scripts/perl>perl fix.pl base.gtx >base.txt
> 
> Here is my python script:
> 
> path="c:/scripts/perl/"
> subprocess.call(['perl','fix.pl','base.gtx >base.txt',path])
> 
> I also tried this alternative:
> 
> subprocess.Popen(['perl','fix.pl','base.gtx >base.txt',path]) #same
> result from this method.
> 
> The above script generates the base.txt file but has no content in it.
> 
> any ideas as to why the resulting text file is empty? Am I using the
> correct python commands to run the above manual process?

I'm surprised that base.txt is generated at all, I'd expect fix.pl to look 
for a file named "base.gtx >base.txt" and complain when it doesn't find 
that.

I think the following should work:

with open("c:/scripts/perl/base.txt", "w") as f:
    subprocess.check_call(
        ["perl", 
         "c:/scripts/perl/fix.pl", 
         "c:/scripts/perl/base.gtx"], 
        stdout=f)