sudo chown -R username:group directory
sudo chown newUser file.txt
<!--
This is to change permissions for a directory in linux :
755 is better but for local operations you shoul be ok using 777
the -R is to apply to all containing folders. It stands for recursive.
-->
<!-- 755 is safer -->
chmod 755 -R folder-Name
<!-- 777 is mighty and powerful ;) -->
chmod 777 -R folder-Name