Remove number of bytes from beginning of file

Question

I want to copy a file without the first 256 bytes.

Is there a nice way to do it in python?

I guessing that the simple way is to read byte-byte with a counter and then start copy only when it get to 256.

I was hoping for more elegant way.

Thanks.

Solution 1

f = open('filename.ext', 'rb')
f.seek(255) # skip the first 255 bytes
rest = f.read() # read rest

Solution 2

with open('input', 'rb') as in_file:
    with open('output', 'wb') as out_file:
        out_file.write(in_file.read()[256:])

Solution 3

Use seek to skip the first 256 bytes, then copy the file in chunks to avoid reading the entire input file into memory. Also, make sure to use with so that the file is closed properly:

with open('input.dat', 'rb') as inFile:
    inFile.seek(256)
    with open('output.dat', 'wb') as outFile:
        for chunk in iter(lambda: inFile.read(16384), ''):
            outFile.write(chunk)

Comments

[Ajasja]

Note that in python 3 you have to do b'' otherwise the copy will not finish.