Trouble calling external commands from Python

Asked Jan 10 '17 at 22:50

Active Jan 10 '17 at 23:15

Viewed 36 times

I am trying to copy some directories of zipped files from an AWS bucket to a Windows machine using Python in Eclipse (Pydev).

When I use the following command:

result = subprocess.Popen([r'aws s3 cp s3://myBucket/' + str(someInt) + '/ ' + output_dir + ' --recursive'], stdout=subprocess.PIPE)

I get an error:

FileNotFoundError: [WinError 2] The system cannot find the file specified

However, if I paste the evaluated argument into the Windows command line, it copies the files successfully. I have also been able to execute the AWS command using R successfully:

result <- shell(paste0("aws ", "s3 ", "cp ", "s3://myBucket/", someInt, "/ ", output_dir, " --recursive"))

So, I know that the files exist and that I am able to copy them with other methods. I must be missing some simple syntax error with my Python command.

Update: Here is the working solution:

result = subprocess.Popen(['aws', 's3', 'cp', r's3://myBucket' + str(someInt) + '/', output_dir, '--recursive'], stdout=subprocess.PIPE)

edited Jan 10 '17 at 23:15

asked Jan 10 '17 at 22:50

Jeff

Check out http://stackoverflow.com/questions/12605498/how-to-use-subprocess-popen-python – DonCristobal Jan 10 '17 at 22:52
Yes, I saw that. I have used subprocess.Popen before and it worked for me. In this specific instance, it is giving me trouble. – Jeff Jan 10 '17 at 22:54
1

I believe Popen expects a list such as ['aws', 's3', 'cp', ...] – DonCristobal Jan 10 '17 at 22:58
Looks like that was the main issue. Thank you. – Jeff Jan 10 '17 at 23:14

Trouble calling external commands from Python

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