Fix Permission problems on servers

^{Notice: If you are not familiar with linux and unsure how to
correctly execute commands, we advise that you
backup current server, before making the below changes.}

Many times, on VPS servers (ubuntu, linux, debian, etc…) you might face an issue, like in PHP, showing an error message like:

Warning: rename/move/write/access/create ….. Permission denied in  /path/your_file.php

Most times, the reason could be that one user (like root) owns the directory, and another user (i.e. www-data, which is apache instance user) tries to modify the file. For me, the best solution to such problems was to create a Group of users (let’s name it myusers), consisting of both root and www-data:

groupadd myusers
gpasswd -a www-data   myusers 
gpasswd -a root       myusers
gpasswd -a other_user myusers

and then give that group the needed privileges (change your desired path):

sudo chown -R :myusers /var/www/

So, you can modify the file/folder from i.e. FTP or terminal, and also from Web-interface (which is Apache).  And finally, assign correct chmod permissions to directories and files :

find /var/www/ -type d -exec chmod u+rwx,g+rwx,o+rx {} \;
find /var/www/ -type f -exec chmod u+rw,g+rw,o+r {} \;

That’s all . ^{(btw, sometimes, instead of rwx you might need rwxs)}

_Definitions:
*u = user, g = group, o = others
* r = read (same as 4), w = write(same as 2), x = execute(same as 1)
_{i.e. rwx is 4+2+1 = 7; So,  u+rwx,g+rwx,o+rx is same as 775}

_______

Additional resources:

• question: group-permissions-allow-but-still-get-permission-denied
• question: multiple-owner-of-same-folder
• question: reset-default-permissions-for-var-www
• question: change-folder-permissions-and-ownership
• question: whats-the-simplest-way-to-edit-and-add-files-to-var-www
• ^{(Combined command was made from this source)}