In place replacement of text in a file in Python

Question

I am using the following code to upload a file on server using FTP after editing it:

import fileinput

file = open(\'example.php\',\'rb+\')

for line in file         


        

Answer 1

Replacing stuff in a file only works well if original and replacement have the same size (in bytes) then you can do

with open('example.php','rb+') as f:
    pos=f.tell()
    line=f.readline()
    if b'Original' in line:
        f.seek(pos)
        f.write(line.replace(b'Original',b'Replacement'))

(In this case b'Original' and b'Replacement' do not have the same size so your file will look funny after this)

Edit:

If original and replacement are not the same size, there are different possibilities like adding bytes to fill the hole or moving everything after the line.