Nginx

Logs Commands

Configure Nginx logging formats, implement log rotation with logrotate, monitor access and error logs in real-time, and analyze traffic patterns for debugging and security monitoring.

8 commands

Pro Tips

Use custom log formats with `log_format` to include important headers like X-Forwarded-For for proxy setups.

Disable access logging for static assets like images/CSS with `access_log off;` in specific location blocks to reduce I/O.

Send logs to syslog with `access_log syslog:server=unix:/dev/log` for centralized logging infrastructure.

Use `tail -f /var/log/nginx/error.log` to monitor errors in real-time during deployment and troubleshooting.

Common Mistakes

Log files can grow rapidly under high traffic. Implement proper log rotation to prevent disk space issues.

After log rotation, send a `nginx -s reopen` signal to make Nginx start writing to new log files.

Commands

Find 404 errors

$ sudo grep " 404 " /var/log/nginx/access.log | tail -20

Show recent 404 errors

View access log

$ sudo tail -f /var/log/nginx/access.log

Follow access log in real-time

Truncate logs

$ sudo truncate -s 0 /var/log/nginx/access.log /var/log/nginx/error.log

Clear log files without deleting them

View error log

$ sudo tail -f /var/log/nginx/error.log

Follow error log in real-time

Show last 100 errors

$ sudo tail -n 100 /var/log/nginx/error.log

Show last 100 lines of error log

Search in access log

$ sudo grep "pattern" /var/log/nginx/access.log

Search for pattern in access log

Top requesting IPs

$ sudo awk '{print $1}' /var/log/nginx/access.log | sort | uniq -c | sort -rn | head -20

Show top 20 IPs by request count

Top requested URLs

$ sudo awk '{print $7}' /var/log/nginx/access.log | sort | uniq -c | sort -rn | head -20

Show top 20 requested URLs