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Adds title, description, type, domain, and tags frontmatter to every doc for improved KB semantic search. The description field is prepended to every search chunk, and domain/type/tags enable filtered queries. Type values: context, guide, runbook, reference, troubleshooting Domain values match directory structure (networking, docker, etc.) Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
153 lines
3.3 KiB
Markdown
153 lines
3.3 KiB
Markdown
---
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title: "Bash Service Management Examples"
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description: "Bash script examples for systemd service installation, lifecycle management (start/stop/restart/status/logs), and process monitoring with PID-based health checks and auto-restart."
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type: reference
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domain: development
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tags: [bash, systemd, service-management, process-monitoring, scripting]
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---
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# Bash Service Management Examples
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## Systemd Service Script
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```bash
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#!/bin/bash
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set -euo pipefail
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SERVICE_NAME="myapp"
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SERVICE_FILE="/etc/systemd/system/${SERVICE_NAME}.service"
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usage() {
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echo "Usage: $0 {install|start|stop|restart|status|logs|uninstall}"
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exit 1
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}
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install_service() {
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echo "Installing ${SERVICE_NAME} service..."
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sudo tee "$SERVICE_FILE" > /dev/null << EOF
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[Unit]
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Description=My Application Service
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After=network.target
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Wants=network.target
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[Service]
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Type=simple
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User=myapp
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Group=myapp
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WorkingDirectory=/opt/myapp
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ExecStart=/opt/myapp/bin/myapp
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Restart=always
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RestartSec=10
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Environment=NODE_ENV=production
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[Install]
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WantedBy=multi-user.target
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EOF
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sudo systemctl daemon-reload
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sudo systemctl enable "$SERVICE_NAME"
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echo "Service installed and enabled"
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}
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manage_service() {
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local action="$1"
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echo "${action^}ing ${SERVICE_NAME} service..."
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sudo systemctl "$action" "$SERVICE_NAME"
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echo "Service ${action}ed successfully"
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}
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show_status() {
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echo "=== Service Status ==="
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sudo systemctl status "$SERVICE_NAME" --no-pager -l
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echo
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echo "=== Service Logs (last 20 lines) ==="
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sudo journalctl -u "$SERVICE_NAME" --no-pager -n 20
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}
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show_logs() {
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echo "Following logs for ${SERVICE_NAME}..."
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sudo journalctl -u "$SERVICE_NAME" -f
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}
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uninstall_service() {
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echo "Uninstalling ${SERVICE_NAME} service..."
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sudo systemctl stop "$SERVICE_NAME" || true
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sudo systemctl disable "$SERVICE_NAME" || true
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sudo rm -f "$SERVICE_FILE"
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sudo systemctl daemon-reload
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echo "Service uninstalled"
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}
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case "${1:-}" in
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install)
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install_service
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;;
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start|stop|restart)
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manage_service "$1"
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;;
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status)
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show_status
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;;
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logs)
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show_logs
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;;
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uninstall)
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uninstall_service
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;;
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*)
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usage
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;;
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esac
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```
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## Process Monitoring Script
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```bash
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#!/bin/bash
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set -euo pipefail
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PROCESS_NAME="myapp"
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RESTART_COMMAND="/opt/myapp/start.sh"
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LOG_FILE="/var/log/myapp-monitor.log"
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PID_FILE="/var/run/myapp.pid"
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log_message() {
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echo "$(date '+%Y-%m-%d %H:%M:%S') - $1" | tee -a "$LOG_FILE"
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}
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check_process() {
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if [[ -f "$PID_FILE" ]]; then
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local pid=$(cat "$PID_FILE")
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if kill -0 "$pid" 2>/dev/null; then
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return 0 # Process is running
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else
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rm -f "$PID_FILE"
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return 1 # Process is not running
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fi
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else
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return 1 # PID file doesn't exist
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fi
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}
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restart_process() {
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log_message "Attempting to restart $PROCESS_NAME..."
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if $RESTART_COMMAND; then
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log_message "$PROCESS_NAME restarted successfully"
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else
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log_message "Failed to restart $PROCESS_NAME"
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exit 1
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fi
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}
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main() {
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if ! check_process; then
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log_message "$PROCESS_NAME is not running"
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restart_process
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else
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log_message "$PROCESS_NAME is running normally"
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fi
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}
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main "$@"
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``` |