File Permissions

There are two key commands for working with file permissions on Linux, chmod and chown. For a brilliant summary of chmod see Tutorial for chmod.

One useful command for viewing file ownership and permissions is getfacl filename.ext which gives a clear and handy summary, clearer than ls -l filename.ext in my opinion. If you find the command does not work then you might need to install it, on Debian you need to do the following:
apt install acl


  • chmod u+x - add execute permissions for the current user
  • chmod g-w example.txt - remove write permissions for the group
  • chmod o-r example.txt - remove read permission for all users except "group" and "user"