Give specific user permission to write to a folder using +w notation
You could use setfacl:
setfacl -m u:username:rwx myfolder
This sets permissions for specific users, without changing the ownership of the directory.
Check out the man page for further details and examples.
EDIT: Highlighted points in comment
- setfacl = set File ACL, ACL = Access Control List hence for short "setFacl"
- If you want to apply it recursively to all the subdirectories: add the -R flag like this:
setfacl -R -m u:username:rwx myfolder
If you want to change the user owning this file or directory (folder), you will have to use the command chown. For instance, if you run
sudo chown username: myfolder
the user owning myfolder will be username. Then you can execute
sudo chmod u+w myfolder
to add the write permission to the username user.
But if you want to add this user to the group associated with "myfolder", you can run
sudo usermod -a -G groupname username
and then execute
sudo chmod g+w myfolder
to add the write permission to the group.
No this is not possible. You can either change the owner of the file with
[sudo] chown username: foldername
or you can add the user to the group that owns the file with
usermod -a -G {group-name} username