Ubuntu – How to change a set of files Permsissions from Root to user

Just add the -R option to recursively change the permissions of files. An example, recursively add read and write permissions for the owner and group on foldername:

chmod -R ug+rw foldername

Permissions will be like 664 or 775.

Setting the permissions to 777 is highly discouraged. You get errors in either Apache or your editor regarding permissions because apache runs under a different user (www-data) than you.

If you want to write to /var/www, add yourself to the www-data group and set umask+permissions accordingly.

• Add yourself to the www-data group: sudo adduser $USER www-data
• Change the ownership of the files in /var/www: sudo chown -R www-data:www-data /var/www
• Change the umask, so newly created files by Apache grants write permissions to the group too. Add umask 007 to /etc/apache2/envvars.
• Grant yourself (technically, the group www-data) write permissions: sudo chmod -R g+w /var/www.

The chown command is to change user and group ownership, to change permissions, you need chmod. So, once you have set the group ownership to pandya using chown as you have, change the permissions to give the group write access:

chmod -R g+w /media/pandya/Ext4/

From man chmod:

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.

A combination of the letters ugoa controls which users' access to the file will be changed: the user who owns it (u), other users in the file's group (g), other users not in the file's group (o), or all users (a). If none of these are given, the effect is as if a were given, but bits that are set in the umask are not affected.

The operator + causes the selected file mode bits to be added to the existing file mode bits of each file; - causes them to be removed; and = causes them to be added and causes unmentioned bits to be removed

-R, --recursive

change files and directories recursively

So, g+w means "give users that belong to the file's group write access" and -R means apply to all files and subdirectories recursively.