groupwritable

#!/bin/bash

# Setting up permissions for the $dir. All subdirectories
# therein that contain $markfile must be group
# writable and have s-bit set. Files group writable/readable.
#
# For crontab: run 'crontab -e' and add
# 0 */2 * * 1-5 /path/to/groupwritable directory/path

# Copyright (C) 2018 ivan.tervanto /at/ aalto.fi

# Released under the GNU General Public License


dir={1:?Usage $0 }
markfile='.groupwritable'


setperm() {
  # we check files directories before modifying them
  # thus avoiding extra filesystem load

  #DEBUG='echo'  # if uncommented, makes dry run
  local d=${1%/*}
  # set g+rws to the directories
  $DEBUG find $d -type d ! -perm -g+s,g+w,g+r -exec chmod g+rws {} \;
  # set u+rwX,g+rwX,o-wx to files
  $DEBUG find $d -type f \( ! -perm /g+w  -o -perm /o+w \) -exec chmod u+rwX,g+rwX,o-wx {} \;
}

# needs to be exported so that one could use the function
# in the subshell, like in case of 'find'
export -f setperm

# find all the subdirectories with the $markfile and
# run 'setperm' function for them
find $dir -name $markfile -exec bash -c 'setperm {}' \;