How can I get the Unix permission mask from a file? [duplicate]

Answer 1

oct(os.stat('file').st_mode)[4:]

Answer 2

Another way to do it if you don't want to work out what stat means is to use the os.access command http://docs.python.org/library/os.html#os.access BUT read the docs about possible security issues

For instance to check permissions on the file test.dat which has read/write permissions

os.access("test.dat",os.R_OK)
>>> True

#Execute permissions
os.access("test.dat",os.X_OK)
>>> False

#And Combinations thereof
os.access("test.dat",os.R_OK or os.X_OK)
>>> True

os.access("test.dat",os.R_OK and os.X_OK)
>>> False

Answer 3

I think this is the clearest way of getting a file's the permission bits:

stat.S_IMODE(os.lstat("file").st_mode)

The os.lstat function, will in case the file is a symlink, give you the mode of the link itself, whereas os.stat dereferences the link. Therefore I find os.lstat the most generally useful.

Here's an example case, given regular file "testfile" and symlink to the latter, "testlink":

import stat
import os

print oct(stat.S_IMODE(os.lstat("testlink").st_mode))
print oct(stat.S_IMODE(os.stat("testlink").st_mode))

This script outputs the following for me:

0777
0666

Answer 4

You can just run a Bash stat command with Popen if you want:

The normal Bash command:

jlc@server:~/NetBeansProjects/LineReverse$ stat -c '%A %a %n' revline.c
-rw-rw-r-- 664 revline.c

And then with Python:

>>> from subprocess import Popen, PIPE
>>> fname = 'revline.c'
>>> cmd = "stat -c '%A %a %n' " + fname
>>> out = Popen(cmd, shell=True, stdout=PIPE).communicate()[0].split()[1].decode()
>>> out
'664'

And here's another way if you feel like searching the directory:

>>> from os import popen
>>> cmd = "stat -c '%A %a %n' *"
>>> fname = 'revline.c'
>>> for i in popen(cmd):
...     p, m, n = i.split()
...     if n != fname:
...         continue
...     print(m)
        break
... 
664
>>> 

Answer 5

There are a lot of file based functions inside the os module im sure. If you run os.stat(filename) you can always interprate the results.

http://docs.python.org/library/stat.html

Answer 6

os.access(path, mode) method returns True if access is allowed on path, False if not.

available modes are :

1. os.F_OK - test the existence of path.
2. os.R_OK - test the readability of path.
3. os.W_OK - test the writability of path.
4. os.X_OK - test if path can be executed.

for example, checking file /tmp/test.sh has execute permission

ls -l /tmp/temp.sh
-rw-r--r--  1 *  *  0 Mar  2 12:05 /tmp/temp.sh

os.access('/tmp/temp.sh',os.X_OK)
False

after changing the file permission to +x 
chmod +x /tmp/temp.sh

ls -l /tmp/temp.sh
-rwxr-xr-x  1 *  *  0 Mar  2 12:05 /tmp/temp.sh

os.access('/tmp/temp.sh',os.X_OK)
True