Linux System Information Commands

Overview

Linux provides a range of commands to gather information about the system's hardware, software, and overall status. These commands are useful for monitoring and troubleshooting system performance and configuration. This document covers basic and commonly used system information commands.

System Information

`uname`

Displays system information.

uname

Example

uname
# Output: Displays the kernel name (e.g., Linux)

`uname -a`

Displays all available system information, including kernel version and system architecture.

uname -a

Example

uname -a
# Output: Linux hostname 5.4.0-42-generic #46-Ubuntu SMP Fri Sep 25 13:00:00 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

`hostname`

Displays or sets the system's hostname.

hostname

Example

hostname
# Output: Displays the current hostname of the system

`hostnamectl`

Displays or changes the system's hostname and other system information.

hostnamectl

Example

hostnamectl
# Output: Provides detailed information about the system's hostname, operating system, and hardware

Hardware Information

`lscpu`

Displays detailed information about the CPU architecture.

lscpu

Example

lscpu
# Output: Displays CPU architecture information including number of CPUs, model name, and more

`lsblk`

Lists information about all available block devices.

lsblk

Example

lsblk
# Output: Lists block devices and their mount points, sizes, and types

`lspci`

Lists all PCI devices on the system.

lspci

Example

lspci
# Output: Lists PCI devices such as graphics cards, network adapters, etc.

`lsusb`

Lists all USB devices connected to the system.

lsusb

Example

lsusb
# Output: Lists USB devices connected to the system along with their vendor and product IDs

`dmidecode`

Displays information about the system's hardware as described in the BIOS.

sudo dmidecode

Example

sudo dmidecode
# Output: Provides detailed information about hardware components, such as memory, CPU, and motherboard

Memory and Disk Usage

`free`

Displays information about system memory usage.

free

Example

free
# Output: Displays memory usage, including total, used, and free memory

`df`

Displays information about disk space usage for mounted filesystems.

df

Example

df
# Output: Displays disk space usage for each mounted filesystem

`du`

Displays disk usage of files and directories.

du <directory>

Example

du /home/user
# Output: Displays disk usage for the '/home/user' directory

`top`

Displays real-time system performance and process information.

top

Example

top
# Output: Displays a real-time, interactive view of system processes and resource usage
# Use 'q' to quit

`htop`

An enhanced version of top with a more user-friendly interface.

htop

Example

htop
# Output: Provides an interactive, user-friendly view of system processes and resource usage
# Use 'q' to quit

System Uptime

`uptime`

Displays how long the system has been running, along with the number of users and load average.

uptime

Example

uptime
# Output: Displays system uptime, number of users, and load averages

Summary

Linux provides a variety of commands to gather detailed system information, from hardware details and disk usage to real-time performance metrics. Understanding these commands helps in monitoring and maintaining system health. For more detailed information on each command, refer to the Linux manual pages.