Using regular expression in subprocess module

Question

I am trying to automate a particular process using subprocess module in python. For example, if I have a set of files that start with a word plot and then 8 digits of numbers. I want to copy them using the subprocess run command.

copyfiles = subprocess.run(['cp', '-r', 'plot*', 'dest'])

When I run the code, the above code returns an error "cp: plot: No such file or directory*"

How can I execute such commands using subprocess module? If I give a full filename, the above code works without any errors.

I'd create a list of candidates first using os.listdir() and filter this list using regex. The pass the matching elements to your subprocess in a loop. — white
– white, Commented Sep 16, 2022 at 13:37
Wildcards are processed by the shell, not by individual utilities such as cp. But the default behavior for subprocess is to not involve a shell at all - you'd need to add shell=True to get this to work (in which case you should supply the command as a single string, rather than a list of individual parameters). — jasonharper
– jasonharper, Commented Sep 16, 2022 at 14:03
@jasonharper please make an answer out of this comment. You are exactly right — Matteo Zanoni
– Matteo Zanoni, Commented Sep 16, 2022 at 14:17
@white I did this, and it works for me. Thanks for the quick solution. — Vinoth Paramanantham
– Vinoth Paramanantham, Commented Sep 17, 2022 at 15:54

user11717481 · Accepted Answer · 2022-09-16 14:01:52Z

0

I have found a useful but probably not the best efficent code fragment from this post, where an additional python library is used (shlex), and what I propose is to use os.listdir method to iterate over folder that you need to copy files, save in a list file_list and filter using a lambda function to extract specific file names, define a command sentence as string and use subproccess.Popen() to execute the child process to copy the files on to a destination folder.

import shlex
import os
import subprocess

# chage directory where your files are located at
os.chdir('C:/example_folder/')

# you can use os.getcwd function to check the current working directory
print(os.getcwd)
 
# extract file names
file_list = os.listdir() 
file_list = list(filter(lambda file_name: file_name.startswith('plot'), file_list))

# command sentence
cmd = 'find test_folder -iname %s -exec cp {} dest_folder ;'

for file in file_list:
    subprocess.Popen(shlex.split(cmd % file))

answered Sep 16, 2022 at 14:01

user11717481

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1 Comment

Vinoth Paramanantham Over a year ago

Thanks for resolving the issue. I just made a list of filenames and used a loop to copy the files to the destination folder.

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