mjhjmtu

Is there a way (with acl's) to protect the contents of a folder? Users should create files inside a folder but not overwrite/edit/delete them. Is this possible?

One might use inotifywait to watch the directory and make changes, such as changing ownership of each new file copied into the directory. In a Debian-based distribution, install the software as follows: apt-get install inotify-tools.

Create a script, perhaps /usr/local/sbin/inbox.sh, as follows.

#!/usr/bin/env bash
inotifywait -m -e create "/path/to/directory" |
while read path event file; do
 if [ "$event" = "CREATE" ]; then
 chown root:root "$path$file"
 fi
done

Give the script permission to execute (chmod 0700 /usr/local/sbin/inbox.sh). Then run it at boot time from, say, /etc/rc.local or whichever RC file is appropriate: /usr/local/sbin/inbox.sh &.

According to the manual, -m monitors indefinitely, and -e watches for a specific event. Within the while loop, it could be possible to receive an event such as CREATE,ISDIR, which indicates the creation of a directory, of course. Directories are not the target of the question; thus the if statement contains a command to respond only to new files, which are represented with the event, CREATE. The path variable from inotifywait has a trailing slash character, so $path and $file can be concatenated without specifying a slash between the two.