Operating System and Kernel Information

In Linux, you can gather detailed information about the operating system and kernel using various commands. Here are some of the most useful commands:

Get detailed system and kernel info:


hostnamectl

Example output:


   Static hostname: rhel9-server
         Icon name: computer-vm
           Chassis: vm
        Machine ID: abcdef123456...
           Boot ID: 123456abcdef...
  Operating System: Red Hat Enterprise Linux 9.2 (Plow)
       CPE OS Name: cpe:/o:redhat:enterprise_linux:9::baseos
            Kernel: Linux 5.14.0-284.el9.x86_64
      Architecture: x86-64

Just kernel name, release, version:


uname -s      # Kernel name
uname -r      # Kernel release
uname -v      # Kernel version
uname -m      # Machine hardware name
uname -a      # All of the above combined

Hostname Information


hostname       # Short hostname
hostname -f    # Fully Qualified Domain Name (FQDN)
hostnamectl    # Includes hostname + OS info + architecture

Hardware and CPU Info


lscpu

Shows detailed CPU architecture including cores, threads, model, and vendor.


lsblk

Lists block devices (disks, partitions).


lshw           # Not installed by default, install via: sudo dnf install lshw


dmidecode      # Needs sudo, shows BIOS, motherboard, and memory info
sudo dmidecode | less

Memory Information


free -h

Shows memory and swap usage in human-readable form.


cat /proc/meminfo

Detailed memory information.

System Uptime


uptime

Shows how long the system has been running, current time, number of users, and load average.


uptime -p      # Pretty uptime (e.g., "up 2 hours, 5 minutes")
uptime -s      # Shows system boot time

System Logs and Boot Messages


dmesg | less

Prints kernel ring buffer messages (hardware, drivers, boot info).

Use dmesg | grep to filter:


dmesg | grep memory
dmesg | grep -i usb

System Information Summary


uname -a
hostnamectl
lsb_release -a          # Shows distribution info (not installed by default)
cat /etc/redhat-release # Preferred way for RHEL

Optional Installations (if not found by default on minimal RHEL 9):


sudo dnf install lshw lsb_release dmidecode net-tools

Common Use Case Summary

Purpose	Command	Description
OS Version	`cat /etc/redhat-release`	Shows the OS version
Kernel Info	`uname -r` or `hostnamectl`	Displays kernel version
Hostname	`hostname`, `hostnamectl`	Shows the system hostname
CPU Info	`lscpu`	Displays CPU architecture information
Memory Info	`free -h`, `/proc/meminfo`	Shows memory usage information
Disk Info	`lsblk`, `df -h`	Shows disk usage information
Boot Messages	`dmesg	less`
System Uptime	`uptime`	Shows system uptime
Hardware Details	`sudo dmidecode`, `lshw`	Shows detailed hardware information