Bash Scripting Challenge - Log Analyzer and Report Generator

# Day 5: Bash Scripting Challenge - Log Analyzer and Report Generator

## Challenge Title: Log Analyzer and Report Generator

## Scenario

You are a system administrator responsible for managing a network of servers. Every day, a log file is generated on each server containing important system events and error messages. As part of your daily tasks, you need to analyze these log files, identify specific events, and generate a summary report.

## Task

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.

# Step 1: Count the total number of lines in the log file

total_lines=$(wc -l < "$log_file")

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.

# Step 2: Count the number of error messages (identified by the keyword "ERROR" in this example)

error_count=$(grep -c -i "ERROR" "$log_file")

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

# Step 3: Search for critical events (lines containing the keyword "CRITICAL") and store them in an array

mapfile -t critical_events < <(grep -n -i "CRITICAL" "$log_file")

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

# Step 4: Identify the top 5 most common error messages and their occurrence count using associative arrays

declare -A error_messages

while IFS= read -r line; do

# Use awk to extract the error message (fields are space-separated)

error_msg=$(awk '{for (i=3; i<=NF; i++) printf $i " "; print ""}' <<< "$line")

((error_messages["$error_msg"]++))

done < <(grep -i "ERROR" "$log_file")

# Sort the error messages by occurrence count (descending order)

sorted_error_messages=$(for key in "${!error_messages[@]}"; do

echo "${error_messages[$key]} $key"

done | sort -rn | head -n 5)

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

# Step 5: Generate the summary report in a separate file

summary_report="log_summary_$(date +%Y-%m-%d).txt"

{

echo "Date of analysis: $(date)"

echo "Log file: $log_file"

echo "Total lines processed: $total_lines"

echo "Total error count: $error_count"

echo -e "\nTop 5 error messages:"

echo "$sorted_error_messages"

echo -e "\nCritical events with line numbers:"

for event in "${critical_events[@]}"; do

echo "$event"

done

} > "$summary_report"


echo "Summary report generated: $summary_report"