best way to copy a big binary file

[snippsat]

how does tqdm know how big the file is?

See that i use os.path.getsize

λ ptpython
>>> import os

>>> os.path.getsize('2.1GB.rar')
2178168457

Return size in bytes,then use unit='B', unit_scale=True,this tell tqdm to count bytes in block size.

If eg use 16 kb buffer_size,will see that the progress bar get a more stuttering way,because of smaller block size.

file_copy(file_name, path_out, buffer_size=16384)