Log Analyzer and Report Generator

Write a Bash script that automates the process of analyzing log files and generating a daily summary report. The script should perform the following steps:

1. Input: The script should take the path to the log file as a command-line argument.

2. Error Count: Analyze the log file and count the number of error messages. An error message can be identified by a specific keyword (e.g., "ERROR" or "Failed"). Print the total error count.

3. Critical Events: Search for lines containing the keyword "CRITICAL" and print those lines along with the line number.

4. Top Error Messages: Identify the top 5 most common error messages and display them along with their occurrence count.

5. Summary Report: Generate a summary report in a separate text file. The report should include:

   • Date of analysis

   • Log file name

   • Total lines processed

   • Total error count

   • Top 5 error messages with their occurrence count

   • List of critical events with line numbers

#!/bin/bash

# Check if log file path is provided as an argument
if [[ $# -eq 0 ]]; then
    echo "Usage: $0 path/to/log/file"
    exit 1
fi

# Set log file
log_file="$1"

# Check if the provided log file exists
if [[ ! -f "$log_file" ]]; then
    echo "Error: log file not found"
    exit 1
fi

# Variables to generate report
date=$(date)
total_line_processed=$(wc -l < "$log_file")
error_count=$(grep -E "ERROR|FAILED" "$log_file" | wc -l)
report_file="log_summary_report_$(date +%Y-%m-%d_%H-%M).txt"

echo "Analyzing log file: $log_file"
echo "Error Count: ${error_count}"

# Use awk to print line number with 'CRITICAL' messages
echo -e "\nCritical Events:"
awk '/CRITICAL/ {print NR, $0}' "$log_file"

# Identify the top 5 most common error messages
grep -E "ERROR|FAILED" "$log_file" | awk -F': ' '{print $NF}' | sort | uniq -c | sort -nr | head -n 5

echo "Generating report in $report_file"
{
    echo "Date of Analysis: $date"
    echo "Log File Name: $log_file"
    echo "Total Lines Processed: $total_line_processed"
    echo "Total Error Count: $error_count"
    echo "Top 5 Error Messages:"
    grep -E "ERROR|FAILED" "$log_file" | awk -F': ' '{print $NF}' | sort | uniq -c | sort -nr | head -n 5
    echo "List of Critical Events with line numbers:"
    awk '/CRITICAL/ {print NR, $0}' "$log_file"
} > "$report_file"

# Archive report file
archive_dir="/home/ubuntu/log_dir"
mkdir -p "$archive_dir"
zip "$archive_dir/report_file.zip" "$report_file"

echo "Report saved in $report_file and archived to $archive_dir."

exit 0

Summary of the Script:

1. Argument Check:

   • The script checks if a log file path is provided as an argument. If not, it displays a usage message and exits.

2. Log File Validation:

   • It verifies whether the provided log file exists. If the file is missing, it throws an error and exits.

3. Variables:

   • Date: Captures the current date.

   • Total Lines Processed: Counts the total number of lines in the log file.

   • Error Count: Uses grep to count occurrences of "ERROR" or "FAILED" in the log file.

4. Log Analysis:

   • Critical Events: Uses awk to print lines containing the word "CRITICAL", along with their line numbers.

   • Top 5 Most Common Errors: Uses grep, awk, sort, and uniq to identify and display the top 5 most frequent error messages.

5. Report Generation:

   • Generates a report summarizing the log analysis (date, log file name, total lines processed, error count, top errors, and critical events).

   • The report is saved in a file named log_summary_report_<date>.txt.

6. Archiving:

   • The report file is zipped and saved in /home/ubuntu/log_dir.

7. Output:

   • Displays the location of the saved report and archive.

---

Key Commands:

• grep: Searches for specific patterns (e.g., "ERROR" or "CRITICAL").

• awk: Extracts and prints specific parts of the log file, such as lines with critical events.

• wc -l: Counts the total lines in the log file.

• sort and uniq: Sorts and counts unique error messages.

• zip: Archives the report.