When setting up Nginx on Ubuntu 15.04, you'll encounter two potential default web root directories:

/usr/share/nginx/html
/var/www/html

The /usr/share/nginx/html location comes from the Nginx package maintainers' default configuration. This follows traditional Unix filesystem hierarchy standards where:

• /usr/share contains architecture-independent data
• Package-maintained files typically reside here

Meanwhile, /var/www/html represents the more conventional Apache-style web root that many sysadmins expect. Ubuntu's LAMP stack defaults to this location.

The key difference in functionality comes down to permissions:

$ ls -ld /usr/share/nginx/html
drwxr-xr-x 2 root root 4096 Jun 15 10:23 /usr/share/nginx/html

$ ls -ld /var/www/html
drwxr-xr-x 2 www-data www-data 4096 Jun 15 10:25 /var/www/html

The www-data user ownership of /var/www/html makes it more web-server friendly out of the box.

To use /usr/share/nginx/html effectively, you might need to adjust permissions:

sudo chown -R www-data:www-data /usr/share/nginx/html
sudo chmod -R 755 /usr/share/nginx/html

Or update your Nginx config explicitly:

server {
    listen 80;
    root /usr/share/nginx/html;
    index index.html;
    
    location / {
        try_files $uri $uri/ =404;
    }
}

Consider these factors when choosing:

• Package updates: Files in /usr/share/nginx/html might get overwritten during upgrades
• Security: /var/www/html is typically better isolated
• Compatibility: Many deployment scripts expect /var/www

If files aren't serving from either location, check:

# Verify Nginx is running
systemctl status nginx

# Check configuration syntax
nginx -t

# Examine error logs
tail -f /var/log/nginx/error.log

Remember to restart Nginx after configuration changes:

sudo systemctl restart nginx

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When working with Nginx on Ubuntu systems, you'll encounter two common default directories for serving web content:

/usr/share/nginx/html
/var/www/html

Both directories may exist simultaneously, but they serve different purposes in the Linux filesystem hierarchy.

The /usr/share/nginx/html location is the traditional Nginx default, following Linux Filesystem Hierarchy Standard (FHS) guidelines where:

• /usr/share contains architecture-independent data files
• Nginx packages typically install sample files here

Meanwhile, /var/www/html has become a common alternative because:

• /var/www is the conventional location for web content
• Many administrators prefer keeping website files under /var

Your ability to access files depends on Nginx configuration. Check your active config with:

grep root /etc/nginx/sites-enabled/*

Example server block showing both possibilities:

server {
    listen 80;
    server_name example.com;
    
    # Option 1: Traditional Nginx default
    # root /usr/share/nginx/html;
    
    # Option 2: Common Apache-style location
    root /var/www/html;
    
    index index.html;
}

If you can't access files in /usr/share/nginx/html, check:

ls -la /usr/share/nginx/html

Ensure Nginx worker process has read access:

sudo chown -R www-data:www-data /usr/share/nginx/html
sudo chmod -R 755 /usr/share/nginx/html

For production systems, we recommend:

1. Using /var/www/yourdomain.com/html structure
2. Creating specific Nginx server blocks for each site
3. Maintaining proper SELinux contexts if enabled

Example deployment script:

#!/bin/bash
DOMAIN="example.com"
WEB_ROOT="/var/www/${DOMAIN}/html"

sudo mkdir -p ${WEB_ROOT}
sudo chown -R $USER:$USER ${WEB_ROOT}
sudo chmod -R 755 /var/www