How to check error logs in Linux?

To check the error log, you can use the following command:

1. Check the system log (syslog):
2. Monitor system log files in real-time by using “tail -f /var/log/syslog”.
3. Check the entire content of the system log file by using the command “cat /var/log/syslog.”
4. View application logs:
5. Check the Apache web server’s error log in real-time by using the “tail -f” command, for example: tail -f /var/log/apache2/error.log.
6. Use the cat command to view the entire log file, for example: cat /var/log/apache2/error.log to check the error logs of the Apache web server.
7. View the logs for a specific service.
8. The log files for each service may be stored in different locations, typically under the /var/log directory. You can use the command ls /var/log to see available log files.
9. Common service log file locations include:
   Apache web server: /var/log/apache2/error.log or /var/log/httpd/error_log
   Nginx web server: /var/log/nginx/error.log
   MySQL database: /var/log/mysql/error.log
   SSH server: /var/log/auth.log

Please note that the above command may require administrator privileges (sudo) to execute.