Chmod recursively

Question

I have an archive, which is archived by someone else, and I want to automatically, after I download it, to change a branch of the file system within the extracted files to gain read access. (I can't change how archive is created).

I've looked into this thread: chmod: How to recursively add execute permissions only to files which already have execute permission as into some others, but no joy.

The directories originally come with multiple but all wrong flags, they may appear as:

drwx------
d---r-x---
drwxrwxr-x
dr--r-xr--

Those are just the few I've discovered so far, but could be more.

find errors when tries to look into a directory with no x permission, and so doesn't pass it to chmod. What I've been doing so far, is manually change permissions on the parent directory, then go into the child directories and do the same for them and so on. But this is a lot of hand labour. Isn't there some way to do this automatically?

I.e. how I am doing it now:

do:

$ chmod -R +x
$ chmod -R +r

until I get no errors, then

$ find -type f -exec chmod -x {} +

But there must be a better way.

Answer 1

You can use chmod with the X mode letter (the capital X) to set the executable flag only for directories.

In the example below the executable flag is cleared and then set for all directories recursively:

~$ mkdir foo
~$ mkdir foo/bar
~$ mkdir foo/baz
~$ touch foo/x
~$ touch foo/y

~$ chmod -R go-X foo 
~$ ls -l foo
total 8
drwxrw-r-- 2 wq wq 4096 Nov 14 15:31 bar
drwxrw-r-- 2 wq wq 4096 Nov 14 15:31 baz
-rw-rw-r-- 1 wq wq    0 Nov 14 15:31 x
-rw-rw-r-- 1 wq wq    0 Nov 14 15:31 y

~$ chmod -R go+X foo 
~$ ls -l foo
total 8
drwxrwxr-x 2 wq wq 4096 Nov 14 15:31 bar
drwxrwxr-x 2 wq wq 4096 Nov 14 15:31 baz
-rw-rw-r-- 1 wq wq    0 Nov 14 15:31 x
-rw-rw-r-- 1 wq wq    0 Nov 14 15:31 y

A bit of explaination:

• chmod -x foo - clear the eXecutable flag for foo
• chmod +x foo - set the eXecutable flag for foo
• chmod go+x foo - same as above, but set the flag only for Group and Other users, don't touch the User (owner) permission
• chmod go+X foo - same as above, but apply only to directories, don't touch files
• chmod -R go+X foo - same as above, but do this Recursively for all subdirectories of foo