Introduction to log files of linux system

Log files are log files or collections of files specifically used to record system operation events, and log files are usually saved in the / var/log directory.

Here are a few important log files:

/ var/log/messages: includes the overall system information, as well as logs during system startup.

/ var/log/syslog: unlike the / etc/log/messages log file, it only records warnings, often information about system problems.

/ var/log/user.log: a log that records user information at all levels.

/ var/log/auth.log: contains system authorization information, including permission mechanisms for user login and use, etc.

Log files are divided into event log and message log:

Event log

The event log records events that occur during the execution of the system to provide tracking that can be used to understand the activity of the system and to diagnose problems. They are critical to understanding the activities of complex systems, especially in applications with less user interaction.

It can also be used to combine log file entries from multiple sources. This method, combined with statistical analysis, can produce correlations between seemingly unrelated events on different servers. Other solutions use web-wide queries and reports.

Message log

Internet Relay chat (IRC), instant messaging (IM) programs, peer-to-peer file sharing clients with chat capabilities and multiplayer games (especially MMORPG) usually have the ability to automatically record (that is, save) text communications.

Message logs are almost generic plain text files, but IM and VoIP clients (which support text chat, such as Skype) can save them in HTML files or in a custom format for easy reading and encryption.

These are the details of where the linux log files are. Please pay attention to other related articles for more information.