Set permissions based on user permissions

Question

Because of the default umask settings on my systems, file permissions always default to no access for group and other. This is fine typically but annoying when I'm installing software that I need others to access. Is there a quick way I can reset permissions of all files and folders in a tree after an install based on the use permissions.

Basically copy user except for write.

rwx------ to rwxr-xr-x
rw------- to rw-r--r--

Answer 1

You can use find to do this :

find <dirpath> -perm 700 -type d -exec chmod 755 {} \;  ## For directories
find <dirpath> -perm 600 -type f -exec chmod 644 {} \;  ## For files

Answer 2

You could do something like:

find . ! -type l -print0 |
  perl -0 -lne '
    $m = (lstat$_)[2] & 07777;
    $u = ($m >> 6) & 5;
    chmod $m | $u | ($u<<3), $_'

That is, take the user permissions, remove the write bit (& 5) and or that to the group and other permissions.

Answer 3

Assuming that you're a well behaved unix user and don't have whitespaces in filenames:

for file in $(find . -type f -o -type d)
do \
    user_perm=$(stat -c %a $file |cut -c1)
    other_perm=$(($user_perm&5))
    chmod $user_perm$other_perm$other_perm $file
done