Process checks ps - snapshot of current process top - this provides dynamic view of running system pgrep - looks htrough the currently running process and lists the process IDs pgrep [options] pattern
Service checks systemctl - gives log for system and controls systemd systemctl list-units - units are a managed resource this command helps to check the acitve services,sockets,mounts
Log checks journalctl -u ssh - print logs of the specific service tail -n - 50 this shows the last 50 entries
Mini troubleshooting steps