setfacl

• Set File Access Controll List
• Access Control List (ACL) provides flexible permission mechanism
• It's an additional permission system
• Allows access for a user without having to add it to a group (g) or to allow access to "others" (o)

# Modify a file ACL
setfacl -m u:"user":rwx "file" # Set rwx to a user
setfacl -m g:"group":rwx "file" # Set rwx to a group

# Recursive mode in a directory
setfacl -Rm "entry" "directory"

# Remove a ACL entry from a user
setfacl -x u:"user" "file"

# Remove all ACL entries from everyone
setfacl -b "file"

• Files with ACL receives a + in the permissions listing (ls)
• Even with write permission, users cannot delete a file with ACL

# save and restore permissions
getfacl -R /some/path > permissions.txt
setfacl --restore=permissions.txt