Painlessly setting the mode of files / folders in a tree.

FixPerms.sh

#!/bin/bash
#
# POSIX permissions for a folder need to include the execute bit so you can list
# their contents. But you don't want the execute flag on files, otherwise 
# someone could try to run them like a program.
#
# For this reason,
#
# chmod -R $some_mode $path_to_folder
#
# is generally a bad idea.
#
# See http://en.wikipedia.org/wiki/File_system_permissions#Notation_of_traditional_Unix_permissions
# for more.
#
# Fortunately find(1) is pretty powerful and can save you a lot of time...
 
# To change the permissions of all directories in a folder and all sub-folders 
# to $dir_perms (i.e.: 755 or u=rwx,og=rx):

find $path_to_folder -depth -type d -exec chmod $dir_perms '{}' \;

# ... literally, "Find all directories in $path_to_folder (including 
# $path_to_folder) in depth-first order and, for each directory, execute 
# `chmod $dir_perms` on it.
#
# If I remember correctly, depth-first order helps avoid errors when you have 
# read-and-write-but-not-execute permissions to a set of nested folders. But I 
# could be wrong.
#
# To change the permissions of all files in a folder and all sub-folders to 
# $file_perms (i.e.: 644 or u=rw,og=r):

find $path_to_folder -type f -exec chmod $file_perms '{}' \;

# ... literally, "Find all files in $path_to_folder and, for each file, execute
# `chmod $file_perms` on it.