list directory contents

-h, --human-readable
       with -l, print sizes in human readable format (e.g., 1K 234M 2G)

-a, --all
       do not ignore entries starting with .

-l     use a long listing format

-d, --directory
       list directory entries instead of contents, and do not dereference symbolic links

List information about the FILEs (the current directory by default).  Sort entries alphabetically if none
of -cftuvSUX nor --sort is specified.

Commands separated  by  a ; are executed sequentially; the shell waits for each command to terminate in turn.  The
return status is the exit status of the last command executed.

execute a command as another user

change file mode bits

The  format  of  a  symbolic  mode  is  [ugoa...][[+-=][perms...]...], where perms is either zero or more
letters from the set rwxXst, or a single letter from the set ugo.  Multiple symbolic modes can be  given,
separated by commas.

Change the mode of each FILE to MODE.