Convert bash script to python

Question

I have a bash script and i want to convert it to python.

This is the script :

mv $1/positive/*.$3 $2/JPEGImages
mv $1/negative/*.$3 $2/JPEGImages
mv $1/positive/annotations/*.xml $2/Annotations
mv $1/negative/annotations/*.xml $2/Annotations
cut -d' ' -f1 $1/positive_label.txt > $4_trainval.txt

My problem is : i didn't found how to past positive_label.txt in $4_trainval.txt.

This is my try, it's the first time i work with python. please help me to make it work. thank you.

import sys # Required for reading command line arguments
import os # Required for path manipulations
from os.path import expanduser # Required for expanding '~', which stands for home folder. Used just in case the command line arguments contain "~". Without this, python won't parse "~"
import glob
import shutil


def copy_dataset(arg1,arg2,arg3,arg4):
    path1 = os.path.expanduser(arg1)
    path2 = os.path.expanduser(arg2) # 
    frame_ext = arg3 # File extension of the patches  
    pos_files = glob.glob(os.path.join(path1,'positive/'+'*.'+frame_ext))
    neg_files = glob.glob(os.path.join(path1,'negative/'+'*.'+frame_ext))
    pos_annotation = glob.glob(os.path.join(path1,'positive/annotations/'+'*.'+xml))
    neg_annotation = glob.glob(os.path.join(path1,'negative/annotations/'+'*.'+xml))

    #mv $1/positive/*.$3 $2/JPEGImages
    for x in pos_files:
        shutil.copyfile(x, os.path.join(path2,'JPEGImages'))

    #mv $1/negative/*.$3 $2/JPEGImages
    for y in neg_files:
        shutil.copyfile(y, os.path.join(path2,'JPEGImages'))

    #mv $1/positive/annotations/*.xml $2/Annotations
    for w in pos_annotation:
        shutil.copyfile(w, os.path.join(path2,'Annotations'))

    #mv $1/negative/annotations/*.xml $2/Annotations
    for z in neg_annotation:
        shutil.copyfile(z, os.path.join(path2,'Annotations'))

    #cut -d' ' -f1 $1/positive_label.txt > $4_trainval.txt
    for line in open(path1+'/positive_label.txt')
        line.split(' ')[0]

Answer 1

Without testing, something like that should works.

#cut -d' ' -f1 $1/positive_label.txt > $4_trainval.txt
positive = path1+'/positive_label.txt'
path4 = os.path.join(arg4, '_trainval.txt')

with open(positive, 'r') as input_, open(path4, 'w') as output_:
    for line in input_.readlines():
        output_.write(line.split()[0] + "\n")

This code defines the two files we will work with and opens both. The first is opened in read mode, the second in write mode. For each line in the input file, we write the first find data separated by a space to the output file.

Check Reading and Writing Files in Python for more informations about files into Python.