Change permission on a string of directories

Question

I have a string of directories and i want to change the permission on all of these directories to 775 (rwxrwxr-x) with a command like chmod.

The problem is that the string is editable so it can be different from user to user, so chmod -R doesn't work because one user may have

/apple/a/b 

while another user has

/android/a/b/c/d

Thanks for the help :)

Answer 1

If the variable string contains the path /a/b/c/d, the following instructions will change the permissions of /a, /a/b, /a/b/c and /a/b/c/d:

(
    IFS=/
    unset substring

    for dir in $string; do
        unset IFS
        substring="$substring$dir/"
        test "$substring" != "/" && chmod 755 "$substring"
    done
)

How it works

• The parentheses execute everything in a subshell, so changing the variables IFS and substring won't have any effect outside the subshell.

• IFS=/ sets the internal file separator to slash, so the for loop will split $string at the slashes.

• for dir in $string; do ... done will execute ... once for every component in $string.

  In our example, $dir will take the values , a, b, c and d.

• unset IFS changes the internal file separator back to default, since it will affect slashes in the directory paths.

• substring="$substring$dir/" appends the current value of $dir to $substring.

  In our example, $susbtring will take the values /, /a/, /a/b/, /a/b/c/ and /a/b/c/d/.

• test "$substring" != "/" && chmod 755 "$substring" checks if the current value of $susbtring is different from /.

  If it is, it sets the desired permissions.

Answer 2

Your question is not very clear. Are these directories subdirectories of each other? Anyway, here are some choices:

1. Change permissions on dir1 and all its subdirectories and files

   chmod -R 775 dir1
   

2. Change permissions on dir1 and specific subdirectories

   chmod  775 dir1 dir1/dir2 /dir1/dir2/dir3
   

3. Change permissions on all subdirectories of dir1

   find dir1 -type d -exec chmod 775 {}\;