1. CPU Utilization Threshold Alert

Monitor processor load and trigger a notification when usage exceeds a defined limit. This implementation calculates active CPU time by subtracting the idle percentage reported by top.

#!/usr/bin/env bash
ALERT_LIMIT=75
CURRENT_LOAD=$(top -bn1 | awk '/^%Cpu/ {print 100 - $8}')

if awk "BEGIN {exit !($CURRENT_LOAD > $ALERT_LIMIT)}"; then
    echo "Warning: CPU utilization has reached ${CURRENT_LOAD}%"
    # Integration point for notification webhooks or logging
fi

2. Automated Directory Archival

Create timestamped compressed archives of critical directories. The script validates the source path before execution and isolates the archive name generation for better readability.

#!/usr/bin/env bash
TARGET_DIR="/var/data/project"
ARCHIVE_DEST="/mnt/backups"
TIMESTAMP=$(date +"%F_%H-%M-%S")
ARCHIVE_NAME="proj_backup_${TIMESTAMP}.tar.gz"

if [[ -d "$TARGET_DIR" ]]; then
    tar -czf "${ARCHIVE_DEST}/${ARCHIVE_NAME}" -C "$(dirname "$TARGET_DIR")" "$(basename "$TARGET_DIR")"
    echo "Archive created: ${ARCHIVE_NAME}"
else
    echo "Error: Source directory missing." >&2
    exit 1
fi

3. Log Retention Cleanup

Automatically purge outdated log files to conserve storage. The script uses find with execution batching for efficient file removal.

#!/usr/bin/env bash
LOG_PATH="/var/log/custom_app"
RETENTION_DAYS=14

find "$LOG_PATH" -type f -name "*.log" -mtime +${RETENTION_DAYS} -exec rm -f {} +
echo "Purged logs older than ${RETENTION_DAYS} days from ${LOG_PATH}"

4. Daemon Status Verification

Check the operational state of a critical service and attempt an automatic recovery if it has stopped. System logs are updated via logger for audit trails.

#!/usr/bin/env bash
DAEMON_NAME="postgresql"

if ! systemctl is-active --quiet "${DAEMON_NAME}"; then
    logger -t svc_monitor "Critical: ${DAEMON_NAME} is inactive. Attempting restart."
    systemctl restart "${DAEMON_NAME}"
fi

5. Synchronized Multi-Node Deployment

Distribute application builds across a cluster of servers using rsync. The loop iterates through a predefined node array and mirrors the source directory while removing stale files on the remote targets.

#!/usr/bin/env bash
NODE_LIST=("web-01" "web-02" "web-03")
SRC_PATH="./build/dist/"
REMOTE_PATH="/opt/webapp/current/"

for HOST in "${NODE_LIST[@]}"; do
    echo "Syncing assets to ${HOST}..."
    rsync -az --delete "$SRC_PATH" "admin@${HOST}:${REMOTE_PATH}"
done

6. Storage Capacity Warning

Parse filesystem usage statistics and flag partitions that breach a capacity threshold. The df -P flag ensures POSIX-compliant output formatting for reliable column extraction.

#!/usr/bin/env bash
CAPACITY_LIMIT=85

df -P | tail -n +2 | while read -r fs blocks used avail percent mount; do
    usage_val=${percent%\%}
    if (( usage_val > CAPACITY_LIMIT )); then
        echo "Storage warning: ${mount} is ${usage_val}% full"
    fi
done

7. Batch Service Lifecycle Management

Control multiple related daemons simultaneously. The operation (start, stop, or restart) is passed as a command-line argument, defaulting to restart if omitted.

#!/usr/bin/env bash
SVC_GROUP=("redis" "memcached" "rabbitmq-server")
OPERATION="${1:-restart}"

for SVC in "${SVC_GROUP[@]}"; do
    echo "Executing ${OPERATION} on ${SVC}..."
    systemctl "${OPERATION}" "${SVC}" 2>/dev/null || echo "Failed to control ${SVC}"
done

8. Remote Credential Rotation

Securely update passwords across multiple hosts using an inventory file and expect for interactive SSH handling. New credentials are generated with openssl and logged for future reference.

#!/usr/bin/env bash
HOST_FILE="servers.csv" # Format: ip,user,old_pass,port
CRED_LOG="updated_creds.csv"

while IFS=',' read -r node_addr login_name current_pwd ssh_port; do
    [[ "$node_addr" =~ ^#.*$ || -z "$node_addr" ]] && continue
    fresh_pwd=$(openssl rand -base64 12)

    /usr/bin/expect <<eof chpasswd="" echo="" eof="" exp_continue="" expect="" send="" set="" spawn="" ssh="" stricthostkeychecking="no" timeout="">> "$CRED_LOG"
done < "$HOST_FILE"</eof>

9. Tabular Data Transformation

Extract and filter specific columns from a CSV dataset. This implementation uses awk to skip headers, apply numeric conditions, and output a streamlined report.

#!/usr/bin/env bash
INPUT_CSV="raw_metrics.csv"
OUTPUT_CSV="filtered_report.csv"

awk -F',' 'NR>1 && $4>100 {print $1","$4}' "$INPUT_CSV" > "$OUTPUT_CSV"
echo "Transformation complete. Output written to ${OUTPUT_CSV}"

10. API Endpoint Health Validation

Verify the availability of a web service by inspecting the HTTP response code. The script enforces a connection timeout and evaluates success based on standard 2xx status ranges.

#!/usr/bin/env bash
ENDPOINT="https://api.internal.service/health"
TIMEOUT_SEC=5
HTTP_CODE=$(curl -s -o /dev/null -w "%{http_code}" --max-time $TIMEOUT_SEC "$ENDPOINT")

if [[ "$HTTP_CODE" -ge 200 && "$HTTP_CODE" -lt 300 ]]; then
    echo "Health check successful: Received HTTP ${HTTP_CODE}"
else
    echo "Health check failed: Received HTTP ${HTTP_CODE}" >&2
    exit 1
fi

11. Routine System Inspection

Generate a consolidated diagnostic report covering storage, memory, and recent kernel errors. Output is redirected to a timestamped file for historical tracking.

#!/usr/bin/env bash
REPORT_FILE="/tmp/sys_inspection_$(date +%F).txt"
{
    echo "=== System Inspection Report ==="
    echo "Generated: $(date)"
    echo -e "\n[Storage Usage]"
    df -h | grep -E '^/dev/'
    echo -e "\n[Memory Overview]"
    free -m
    echo -e "\n[Recent Kernel Errors]"
    journalctl -k --priority=err --since "24 hours ago" --no-pager | tail -n 5
} > "$REPORT_FILE"
cat "$REPORT_FILE"

12. Performance Baseline Capture

Record a snapshot of system resource consumption for capacity planning. The script aggregates load averages, virtual memory statistics, and top resource-consuming processes into a structured log.

#!/usr/bin/env bash
SNAPSHOT_DIR="/var/log/perf_baselines"
mkdir -p "$SNAPSHOT_DIR"
OUT_FILE="${SNAPSHOT_DIR}/baseline_$(date +%Y%m%d_%H%M).log"

{
    echo "--- CPU & Load ---"
    uptime
    vmstat 1 3
    echo -e "\n--- Memory Allocation ---"
    free -h
    echo -e "\n--- Top Resource Consumers ---"
    ps -eo pid,user,%cpu,%mem,comm --sort=-%cpu | head -n 11
} > "$OUT_FILE"
echo "Performance snapshot saved to ${OUT_FILE}"