System information

OS & Kernel

Which distribution, which kernel, and how long has it been running?

$ uname -a

$ hostnamectl

$ lsb_release -a

$ cat /etc/os-release

$ uptime

Pretty system overviews for screenshots and quick orientation.

$ fastfetch

$ neofetch

$ inxi -Fz

CPU

lscpu summarizes model, cores, and features; /proc/cpuinfo has the raw per-core details.

$ lscpu

$ cat /proc/cpuinfo

Current CPU load: top in batch mode for a one-shot value, mpstat for per-core statistics, vmstat for a rolling view.

$ top -bn1 | grep "Cpu(s)"

$ mpstat 1 5

$ vmstat 1

Memory

free -h answers the common question; /proc/meminfo has every detail.

$ free -h

$ cat /proc/meminfo

$ vmstat

In free, look at the "available" column, not "free": Linux uses spare RAM for disk cache and releases it when programs need it.

Processes

Snapshot with ps, live view with top or one of its friendlier successors.

$ ps aux

$ ps aux --sort=-%mem | head

$ top

$ htop

$ btop

$ atop

Disks & Partitions

Free space per filesystem, block devices as a tree, and partition tables (root required for fdisk/parted).

$ df -h

$ duf

$ lsblk -f

$ fdisk -l

$ parted -l

Hardware

List devices by bus, or get the full inventory including model numbers.

$ lspci

$ lsusb

$ lshw -short

$ dmidecode -t memory

Temperatures and fan speeds (run sensors-detect once first).

$ sensors

Battery

upower reports detailed battery state; acpi gives the one-line answer. The raw values live in /sys.

$ acpi -b

$ upower -i $(upower -e | grep BAT)

$ cat /sys/class/power_supply/BAT*/capacity

Bluetooth

bluetoothctl is the current tool; hciconfig is deprecated but still found on older systems.

$ bluetoothctl show

$ bluetoothctl devices

$ hciconfig -a

Network Interfaces

$ ip a

$ ifconfig -a

Kernel & Boot Messages

dmesg prints the kernel ring buffer (root on most distributions); journalctl -b shows everything logged since this boot.

$ dmesg

$ dmesg -w

$ journalctl -b

$ lsmod