On Monday December 5 2016 10:41, in comp.lang.python, "BartC" <b...@freeuk.com> wrote:
> On 05/12/2016 15:05, Chris Angelico wrote: >> On Tue, Dec 6, 2016 at 1:11 AM, BartC <b...@freeuk.com> wrote: >>> >>> BTW what does Popen() do when one argument is '*.*'? Will that get >>> expanded to multiple extra arguments, and at what point will it be >>> expanded? >> >> Nope. Popen is not a shell. >> >> It sounds as if you want a nerfed shell. Go ahead! I'm sure one >> exists. It'll frustrate you no end once you get used to a better >> shell, though - always does when I find myself on Windows... > > That's not the point I was making. > > Say you have this program a.py: > > import sys > print (sys.argv) > > And let's say there are just 3 files in the current directory: a.py, > b.py and c.py. > > If run from a Linux shell: > > python a.py * > > The output is: ['a.py', 'b.py', 'c.py'] or something along those lines > (there might be two copies of a.py). And, that's because, before invoking Popen, the SHELL has globbed that '*' argument into the three filenames and substituted those names where the '*' was. If you don't use a shell, then (on Unix), you have to perform the globbing yourself before invoking Popen. > > Are you saying that if someone executes: > > subprocess.Popen(["python","a.py", "*"]) > > the output will be: ['a.py','*']? > > In that case forget Windows vs. Linux, you now have a program that will > get command parameters processed differently depending on whether it was > invoked from a shell or not. Yes. > Or a program that sometimes will see "*" as an argument, and sometimes a > big list of files that merges into all the other arguments. > Yes. -- Lew Pitcher "In Skills, We Trust" PGP public key available upon request -- https://mail.python.org/mailman/listinfo/python-list
