setfacl getfacl command Tips Linux Tips by Donald Burleson

ACLs - Access Control Lists

Under certain circumstances you may find that controlling permissions on an owner/group level are not sufficient.  Perhaps you want to grant just one other user the ability to read a file or maybe you need to share write permissions with several other groups instead of just one.

Some versions and configurations support ACLs or Access Control Lists to allow this finer granularity of access control to files and directories.  With ACLs you can assign very specific permissions to other users who you don't even share a group with.

Typically a file will not have an ACL.  If an ACL has been added to a file you will see a + after the permissions string in an ls ?l listing.

ACLs are very powerful but since they are not typically necessary and support for them is sporadic we will not delve into them in this book.  If you want to get more information about ACLs a good place to start would be the man pages for acl, the setfacl command and the getfacl command.

This is an excerpt from "Easy Linux Commands" by Linux guru Jon Emmons.  You can purchase it for only $19.95 (30%-off) at this link.