1. write a shell script that takes two arguments: a user name and a path, and
   makes that path accessible to the given user ; this means each component of
   the path must be +x and the target file (or directory) must also be +r ...
   see also 'man setfacl' and 'man dirname' ; make sure that no additional
   access (to anyone else) is granted ... only add +x on the target file if at
   least one +x bit is set on it already (anywhere in the acl)

2. Write a C program that prints the ACL of a file given as an argument. Start
   from https://linux.die.net/man/3/acl_get_file ... print both the numeric
   UID and GID and the user and group name with each entry

3. Read addacl.c and try to understand what it does. You can try building and
   running the program if you need to. It's not (too) dangerous.

Homework: Rewrite the script from part 1 as a C program. Make sure the program
does not remove existing ACL entries on the directories or the target file.
1.5 points for updating directory permissions, 1.5 points for the target file,
1 point for style and cleanliness of the code and 1 point for the report.
Describe which APIs (and why) did you use in your solution.

Only hand in the C file and the report (no need to include acl.h or such).