adrigm@AGMStudio:/var/www/html$ sudo chgrp wp-user -R .
adrigm@AGMStudio:/var/www/html$ ls -al
total 224
drwxrwxr-x  6 wp-user wp-user  4096 Dec 18 01:29 .
drwxr-xr-x  3 root    root     4096 Oct 27 22:30 ..
drwxrw-r-x  2 root    wp-user  4096 Dec 15 19:07 archivos
-rw-rw-r--  1 wp-user wp-user   236 Oct 27 23:04 .htaccess
-rw-rw-r--  1 adrigm  wp-user  1412 Dec 18 01:27 index.html
-rw-rw-r--  1 wp-user wp-user   418 Sep  3 05:33 index.php
-rw-rw-r--  1 wp-user wp-user 17935 Sep 28 02:00 licencia.txt
-rw-rw-r--  1 wp-user wp-user 19930 Sep  3 05:33 license.txt
-rw-rw-r--  1 wp-user wp-user  7636 Dec 18 00:45 readme.html
-rw-rw-r--  1 wp-user wp-user  5035 Dec 18 00:45 wp-activate.php
drwxrw-r-x  9 wp-user wp-user  4096 Sep 28 02:00 wp-admin
-rw-rw-r--  1 wp-user wp-user   271 Sep  3 05:33 wp-blog-header.php
-rw-rw-r--  1 wp-user wp-user  1369 Dec 18 00:45 wp-comments-post.php
-rw-rw-r--  1 wp-user wp-user  3401 Oct 27 23:15 wp-config.php
-rw-rw-r--  1 wp-user wp-user  3237 Sep 28 02:00 wp-config-sample.php
drwxrw-r-x  7 wp-user wp-user  4096 Oct 27 23:16 wp-content
-rw-rw-r--  1 wp-user wp-user  3286 Sep  3 05:33 wp-cron.php
drwxrw-r-x 16 wp-user wp-user 12288 Dec 18 00:45 wp-includes
-rw-rw-r--  1 wp-user wp-user  2380 Sep  3 05:33 wp-links-opml.php
-rw-rw-r--  1 wp-user wp-user  3316 Dec 18 00:45 wp-load.php
-rw-rw-r--  1 wp-user wp-user 33710 Dec 18 00:45 wp-login.php
-rw-rw-r--  1 wp-user wp-user  7887 Dec 18 00:45 wp-mail.php
-rw-rw-r--  1 wp-user wp-user 13021 Dec 18 00:45 wp-settings.php
-rw-rw-r--  1 wp-user wp-user 28594 Dec 18 00:45 wp-signup.php
-rw-rw-r--  1 wp-user wp-user  4035 Sep  3 05:33 wp-trackback.php
-rw-rw-r--  1 wp-user wp-user  3061 Dec 18 00:45 xmlrpc.php
adrigm@AGMStudio:/var/www/html$ touch prueba
touch: cannot touch ‘prueba’: Permission denied
adrigm@AGMStudio:/var/www/html$ sudo usermod -a -G wp-user adrigm
adrigm@AGMStudio:/var/www/html$ touch prueba
touch: cannot touch ‘prueba’: Permission denied
adrigm@AGMStudio:/var/www/html$