System Metrics and Cleanup Script

Overview

This Bash script collects system metrics, clears caches, removes old log files, and generates a detailed report. The report is saved in a file named report.txt.

Features

• Captures system metrics before and after cleanup.
• Clears system caches.
• Identifies top memory-consuming processes.
• Identifies the top space-consuming files.
• Deletes log files older than one week.

Script Breakdown

Variables

REPORT="report.txt"  # File to store the system metrics report
LOG_DIR="/var/log"  # Directory containing log files

Capturing System Metrics

The capture_metrics function gathers system information including:

• Free memory
• CPU utilization
• Disk space usage

capture_metrics() {
    echo "=== $1 ===" >> "$REPORT"  # Section header
    echo "Free Memory:" >> "$REPORT"
    free -h >> "$REPORT"  # Displays memory status in a human-readable format
    echo "CPU Utilization:" >> "$REPORT"
    top -b -n1 | grep "Cpu(s)" >> "$REPORT"  # Extracts CPU usage summary
    echo "Disk Space Usage:" >> "$REPORT"
    df -h >> "$REPORT"  # Displays disk space usage
    echo "" >> "$REPORT"  # Adds a blank line for readability
}

Pre-Cleanup Metrics

Before making any changes, the script captures system metrics:

capture_metrics "Before Clearing Caches and Logs"

Clearing System Caches

echo "Clearing system caches..."
sudo su -c "free -h && sync && echo 3 > /proc/sys/vm/drop_caches && free -h" >> "$REPORT"

This clears:

• Page cache
• Dentries
• Inodes

Identifying Top Memory-Consuming Processes

echo "=== Top 10 Memory-Consuming Processes ===" >> "$REPORT"
ps aux --sort=-%mem | head -n 10 >> "$REPORT"

Lists the top 10 processes consuming the most memory.

Identifying Top Space-Consuming Files

echo "=== Top 10 Space-Consuming Files ===" >> "$REPORT"
find / -type f -exec du -h {} + | sort -rh | head -n 10 >> "$REPORT"

Finds the 10 largest files on the system.

Removing Old Log Files

echo "Removing old log files..."
sudo find "$LOG_DIR" -type f -name "*.log" -mtime +7 -exec rm -rf {} \;

Deletes log files older than one week.

Post-Cleanup Metrics

capture_metrics "After Clearing Caches and Old Logs"

Captures system metrics again after the cleanup.

Processor Usage Summary

echo "=== Processor Usage ===" >> "$REPORT"
top -b -n1 | head -n 10 >> "$REPORT"

Displays a processor usage summary.

Final Output Message

echo "Logs older than 1 week cleared. Caches cleared. Report saved to $REPORT."

Indicates the successful execution of the script.

Usage

1. Save the script as system_metrics.sh.
2. Give execution permission:

   chmod +x system_metrics.sh

3. Run the script:

   sudo ./system_metrics.sh

Notes

• The script requires sudo privileges to clear caches and delete logs.
• Be cautious when removing files, as incorrect modifications can delete important data.
• Modify LOG_DIR to target different log directories if necessary.