Follow logs

docker logs [options] <container>

docker logs web-api
docker logs -f --tail 50 web-api
docker logs --since 10m web-api

Server listening on port 3000
GET /api/users 200 12ms

Note Use -f to follow in real time (like tail -f). Combine --tail and --since to avoid dumping thousands of lines. Logs persist until the container is removed.

docker logs -f [--tail <n>] <container>

docker logs -f --tail 100 web-api
docker logs -f --since 5m web-api

Server started on port 3000
GET /api/health 200 2ms
POST /api/users 201 45ms

Note Combine --tail to avoid the initial flood and --since to only see recent entries. Pressing Ctrl+C stops following but does not affect the container.

tail [options] file

tail -n 50 error.log
tail -f /var/log/nginx/access.log
tail -f app.log | grep --line-buffered 'ERROR'

Note -f follows the file in real-time as new lines are appended, which is indispensable for monitoring logs. Use Ctrl+C to stop following. -F will keep retrying if the file is rotated or recreated.