uname -a
Kernel and system info
uname -a
system
hostnamectl
Host and OS metadata
hostnamectl status
systemdsystem
uptime
How long the system has been running
uptime
system
free -h
RAM and swap usage (human readable)
free -h
memory
lscpu
CPU model/cores/flags
lscpu
cpu
lspci
PCI devices (NICs, GPUs, etc.)
lspci | less
hardware
lsblk
Block devices and mount points
lsblk -f
storage
df -h
Filesystem space usage
df -h
storage
du -sh *
Disk usage per directory
du -sh *
storage
find
Find files by name/size/mtime
find /var/log -type f -name '*.log' -mtime -2
files
grep -R
Recursive text search
grep -R "ERROR" /var/log
text
ps aux
All processes with details
ps aux | less
processes
top / htop
Interactive process viewers
top # or: htop
processesmonitor
journalctl -xe
Recent systemd logs with details
journalctl -xe
logs
systemctl daemon-reexec
Reload systemd manager (exec)
sudo systemctl daemon-reexec
systemd
systemctl daemon-reload
Reload unit files after edits
sudo systemctl daemon-reload && sudo systemctl restart nginx
systemd