[SOLVED] How to implement chmod u-w in python

Issue

I know how to implement chmod u+w with the following code:

st = os.stat(dest_file)
os.chmod(dest_file, st.st_mode | stat.S_IWUSR)

But how about u-w?

Solution

st = os.stat(dest_file)
os.chmod(dest_file, st.st_mode & ~stat.S_IWUSR)

Explanation: ~ is the bitwise NOT operator, so a bitwise AND with ~stat.S_IWUSR clears the flag from st.st_mode.

To illustrate with imaginary values:

stat.S_IWUSR                    00001000
~stat.S_IWUSR                   11110111
s.st_mode                       00101001
s.st_mode & ~stat.S_IWUSR       00100001 

Answered By - icecrime

Answer Checked By - Clifford M. (WPSolving Volunteer)