Check the status of a systemd service. Shows whether it's active/inactive/failed, its enabled state, PID, memory usage, and recent log lines from systemctl status output.

Fetch recent journal logs for a systemd service. Supports filtering by time range, priority level, and grep patterns. Useful for debugging service issues and monitoring application output.

List running processes with CPU, memory, and runtime details. Sort by CPU or memory to find resource hogs. Filter by process name to find specific applications.

Show disk space usage by filesystem/mount point. Includes both space and inode usage. Excludes virtual filesystems (tmpfs, devtmpfs) for clarity. Essential for preventing disk-full outages.

Show RAM and swap usage. In detailed mode, includes buffer/cache breakdown from /proc/meminfo. Also reports system load averages for context.

List all listening TCP/UDP ports with their associated processes. Can filter to a specific port number or protocol. Uses 'ss' (modern) with 'netstat' fallback. Useful for checking what services are exposed.

List cron jobs for the current user, a specific user, or all users. Also shows system cron files from /etc/crontab and /etc/cron.d/. Includes cron.daily, cron.weekly, and cron.monthly summaries.

Read, validate, and inspect nginx configuration. Actions: 'show' reads the main config or a specific site, 'test' runs nginx -t validation, 'list_sites' shows enabled/available sites, 'full_config' dumps the fully resolved configuration.

Inspect Docker containers, images, networks, volumes, and resource usage. Gracefully reports if Docker is not installed or the daemon is stopped. The 'overview' action gives a quick summary; 'stats' shows live CPU/memory per container.

Run an aggregate health check across the entire system. Checks load averages, memory/swap usage, disk space (with inode check), failed systemd services, and listening port count. Returns clear HEALTHY/ISSUES DETECTED status with specific warnings and thresholds. This is the go-to tool for a quick 'is everything OK?' check.