Chimie Théorique » scripts_chimie4psmn » DockOnSurf

def tail(f, lines=20):

    total_lines_wanted = lines

    block_size = 1024

    f.seek(0, 2)

    block_end_byte = f.tell()

    lines_to_go = total_lines_wanted

    block_number = -1

    blocks = []

    while lines_to_go > 0 and block_end_byte > 0:

        if block_end_byte - block_size > 0:

            f.seek(block_number * block_size, 2)

            blocks.append(f.read(block_size))

        else:

            f.seek(0, 0)

            blocks.append(f.read(block_end_byte))

        lines_found = blocks[-1].count(b'\n')

        lines_to_go -= lines_found

        block_end_byte -= block_size

        block_number -= 1

    all_read_text = b''.join(reversed(blocks))

    return b'\n'.join(all_read_text.splitlines()[-total_lines_wanted:]).decode()