import os shutil glob
files = glob.iglob(os.path.join(source_dir, "tn*.txt"))
for file in files:
        shutil.copy(file, getcwd())

import os, shutil, glob
source_dir = '/home/test/1/2/'
files = glob.glob(os.path.join(source_dir, "tn*.txt"))
listFile = []
for i in files:
    listFile.append(os.path.basename(i)[2:-4])
copyFile = 'tn'+max(listFile)+'.txt'
os.chdir('/home/test/1')
shutil.copy(os.path.join(source_dir, copyFile), os.getcwd())

>>> lst = ['tn120011.txt', 'tn120017.txt', 'tn120013.txt', 'tn120015.txt']
>>> name = max(lst, key=lambda i: int(i[2:i.rindex('.')]))
>>> name
'tn120017.txt'
>>>

>>> import re
>>> 
>>> lst = ['tn120011.txt', 'tn120017.txt', 'tn120013.txt', 'tn120015.txt']
>>> 
>>> pat = re.compile(r'^tn(\d+)\.txt$')
>>> name = max(lst, key=lambda i: int(pat.search(i).group(1)))
>>> name
'tn120017.txt'
>>>