How to use the command logwatch (with examples)

Logwatch is a command-line tool that helps summarize and analyze various logs for common services. It provides a single report by gathering information from multiple logs, making it easier to monitor and troubleshoot system issues.

Use case 1: Analyze logs for a range of dates at a certain level of detail

Code:

logwatch --range yesterday|today|all|help --detail low|medium|others

Motivation: Analyzing logs for a specific date range can help identify any potential issues or security breaches within a system. By specifying the level of detail, you can control the amount of information displayed in the report, allowing for a more concise analysis.

Explanation:

• --range: Specifies the date range to analyze. It can be set to yesterday to analyze logs from the previous day, today to analyze logs from the current day, all to analyze logs from all available dates, or help to display help information.
• --detail: Determines the level of detail in the report. It can be set to low to include basic summary information, medium to include additional details, or others to include all available information.

Example output:

Logwatch Report for MySystem (All dates)
===============================================

Logfiles processed:   10
Emails sent:          1
...

Use case 2: Restrict report to only include information for a selected service

Code:

logwatch --range all --service apache|pam_unix|etc

Motivation: When troubleshooting specific services, it is often helpful to focus on logs related to those services. By restricting the report to a selected service, you can narrow down the information displayed, making it easier to identify and resolve issues related to that particular service.

Explanation:

• --range: Specifies that logs from all available dates should be included in the report.
• --service: Limits the report to only include information for the specified service. Multiple services can be specified, separated by the pipe character (|).

Example output:

Apache (HTTP Server)
--------------------
Requests:          1234
Errors:            5
...

Conclusion:

Logwatch is a powerful command that simplifies log analysis by summarizing various logs into a single report. By specifying the date range and level of detail, as well as restricting the report to specific services, you can effectively monitor and troubleshoot system issues.