Magento 2 Reset Directories and Files Permissions

gistfile1.txt

find . -type f -exec chmod 644 {} \;                        // 644 permission for files
find . -type d -exec chmod 755 {} \;                        // 755 permission for directory 
find ./var -type d -exec chmod 777 {} \;                // 777 permission for var folder    
find ./pub/media -type d -exec chmod 777 {} \;
find ./pub/static -type d -exec chmod 777 {} \;
chmod 777 ./app/etc
chmod 644 ./app/etc/*.xml

chmod -R g+w *

If you use the +; at the end of the command rather than \; it will process all the files at once rather than one by one.

\; is the same as chmod 644 file1.txt; chmod 644 file2.txt; and +; is the same as chmod 644 file1.txt file2.text.

You will see major performance increases.

Edit:

Also, you don't need the final chmod command on line 9 and you shouldn't resort to 777 permissions.
These will work better:

find . -type f -exec chmod 644 {} +;
find . -type d -exec chmod 755 {} +;
find app/etc generated pub/static var -type d -exec chmod 775 {} +;
find app/etc generated pub/static var -type f -exec chmod 664 {} +;
chmod u+x bin/magento
# You might need to adjust apache/nginx permissions as well, YMMV
chown <my-user>:<my-group> . -R