How to Rotate Nginx Logs with Shell Scripts and Logrotate

Why rotate nginx logs?

By default nginx writes continuously to a single access.log and error.log, which can grow huge over time, making processing difficult. Regular rotation—typically daily—keeps file sizes manageable.

Manual rotation with a shell script

Steps:

Check current log files ( ls /var/log/nginx).

Rename the current log to a dated backup (

mv /var/log/nginx/access.log /var/log/nginx/access.log.$(date +%F)

).

Send the USR1 signal to the nginx master process so it reopens a fresh log file (

kill -USR1 $(ps -ef | grep nginx | grep master | awk '{print $2}')

).

Verify that a new access.log appears and that the old file is archived.

A complete script ( cut_log.sh) automates these steps:

#!/bin/bash
logs_path="/var/log/nginx"
back_logs_path="${logs_path}/$(date -d 'yesterday' +'%F')"
mkdir -p "${back_logs_path}"
cd "${logs_path}" && find . -type f | xargs -i mv {} {}.$(date -d 'yesterday' +'%F')
cd "${logs_path}" && find . -type f | xargs -i mv {} "${back_logs_path}"
kill -USR1 `cat /var/run/nginx.pid`

Scheduling the script

Add a daily cron entry, e.g. 0 0 * * * /bin/bash /etc/nginx/cut_log.sh, to run the script automatically each night.

Using logrotate

logrotate is a standard tool that can rotate and compress logs automatically. The default nginx configuration file /etc/logrotate.d/nginx contains:

/var/log/nginx/*.log {
    daily
    missingok
    rotate 52
    compress
    delaycompress
    notifempty
    create 640 nginx adm
    sharedscripts
    postrotate
        if [ -f /var/run/nginx.pid ]; then
            kill -USR1 `cat /var/run/nginx.pid`
        fi
    endscript
}

Key directives:

daily – rotate each day.

rotate 52 – keep up to 52 archives.

compress and delaycompress – compress after the next rotation.

postrotate – signals nginx to start a new log file.

To test, generate traffic with ab -c 100 -n 10000 http://10.0.0.9/, then force a rotation with logrotate -f /etc/logrotate.d/nginx. The command creates dated log files and, after the next run, compressed .gz archives.

Full workflow

1. Install httpd-tools for ab. 2. Generate load to fill the logs. 3. Run the manual script or let logrotate handle rotation. 4. Verify rotated files with ls -l /var/log/nginx. 5. Ensure the cron job is active.