Linux: System Information Commands

A comprehensive guide to collecting system and hardware information on Linux using command-line tools. Learn how to check CPU, memory, disk, network, and other system details.

Overview

Understanding your Linux system’s hardware and software configuration is essential for system administration, troubleshooting, and optimization. This guide covers various commands to gather detailed system information.

Why Check System Information?

• Troubleshooting: Identify hardware or software issues

• Performance Monitoring: Track resource usage and bottlenecks

• System Inventory: Document hardware specifications

• Compatibility: Verify system requirements before installation

• Security Audits: Review system configuration and users

• Capacity Planning: Monitor resource utilization trends

Basic System Information Commands

General System Information

Display Complete System Information

Show operating system name, system node name, OS release, version, hardware name, and processor type:

uname -a

Example Output:

Linux logicrays-Latitude-5590 5.15.0-157-generic #167-Ubuntu SMP Wed Sep 17 21:35:53 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux

Check Hostname

Display the system’s hostname:

hostname

Example Output:

myserver.example.com
logicrays-Latitude-5590

Get Detailed Hostname Information

Show static and transient hostname with additional details:

hostnamectl

Example Output:

Static hostname: logicrays-Latitude-5590
Icon name: computer-laptop
Chassis: laptop
Machine ID: e7d0df732b0649e49e97a4d764308014
Boot ID: f04e8165d4194c6ca3e0175bb8b470ab
Operating System: Linux Mint 21.3
Kernel: Linux 5.15.0-157-generic
Architecture: x86-64
Hardware Vendor: Dell Inc.
Hardware Model: Latitude 5500

Operating System Information

Get Complete Linux OS Information

Display detailed OS information including version, ID, and URLs:

cat /etc/os-release

Example Output:

NAME="Linux Mint"
VERSION="21.3 (Virginia)"
ID=linuxmint
ID_LIKE="ubuntu debian"
PRETTY_NAME="Linux Mint 21.3"
VERSION_ID="21.3"
HOME_URL="https://www.linuxmint.com/"
SUPPORT_URL="https://forums.linuxmint.com/"
BUG_REPORT_URL="http://linuxmint-troubleshooting-guide.readthedocs.io/en/latest/"
PRIVACY_POLICY_URL="https://www.linuxmint.com/"
VERSION_CODENAME=virginia
UBUNTU_CODENAME=jammy

Alternative OS Information Command:

lsb_release -a

Example Output:

Distributor ID: Ubuntu
Description:    Ubuntu 22.04.3 LTS
Release:        22.04
Codename:       jammy

Check Kernel Version:

uname -r

Example Output:

5.15.0-157-generic

Check OS Type:

uname -o

Example Output:

GNU/Linux

Architecture Information

Check System Architecture

Determine if your system is x64, ARM64, or other architecture:

uname -m

Common Outputs:

• x86_64 - 64-bit Intel/AMD (also called AMD64 or x64)

• aarch64 - 64-bit ARM (ARM64)

• armv7l - 32-bit ARM

• i686 - 32-bit x86

Alternative Architecture Command:

arch

Check if System is 32-bit or 64-bit:

getconf LONG_BIT

Example Output:

64

CPU Information

Display CPU Details

Using lscpu Command

Get detailed CPU architecture information:

lscpu

Example Output:

Architecture:            x86_64
CPU op-mode(s):          32-bit, 64-bit
Byte Order:              Little Endian
Address sizes:           39 bits physical, 48 bits virtual
CPU(s):                  8
Thread(s) per core:      2
Core(s) per socket:      4
Socket(s):               1
Vendor ID:               GenuineIntel
Model name:              Intel(R) Core(TM) i7-8550U CPU @ 1.80GHz
CPU MHz:                 800.057
CPU max MHz:             4000.0000
CPU min MHz:             400.0000

Using /proc/cpuinfo

Display raw CPU information:

cat /proc/cpuinfo

Get CPU Model Only:

cat /proc/cpuinfo | grep "model name" | head -1

Example Output:

model name      : Intel(R) Core(TM) i7-8550U CPU @ 1.80GHz

Using lshw for CPU

Display CPU information using lshw:

lshw -C cpu

or in short format:

lshw -C cpu -short

Count CPU Cores:

nproc

Example Output:

8

Memory Information

Display Memory Usage

Show Free and Used Memory

Display memory in megabytes:

free -m

Example Output:

total        used        free      shared  buff/cache   available
Mem:          31906        15264        9855       1859        6786       14326
Swap:          5119        03232        1887

Display Memory in Gigabytes:

free -g

Human-Readable Memory Display:

free -h

Example Output:

total        used        free      shared  buff/cache   available
Mem:           31Gi        15Gi       9.5Gi       1.8Gi       6.6Gi        13Gi
Swap:         5.0Gi       3.2Gi       1.8Gi

Display Total Available Memory

View detailed memory information:

cat /proc/meminfo

Get Total Memory Only:

cat /proc/meminfo | grep MemTotal

Example Output:

MemTotal:       32672444 kB

Memory Hardware Information

Show Memory Size and Configuration

Using dmidecode:

sudo dmidecode -t memory | grep -i size

Example Output:

Size: 16 GB
Non-Volatile Size: None
Volatile Size: 16 GB
Cache Size: None
Logical Size: None
Size: 16 GB
Non-Volatile Size: None
Volatile Size: 16 GB
Cache Size: None
Logical Size: None

Using lshw for Memory:

lshw -short -C memory

Detailed Memory Information:

sudo dmidecode -t memory

Disk and Storage Information

Disk Usage Commands

Display File System Disk Space Usage

Show disk usage in human-readable format:

df -h

Example Output:

Filesystem      Size  Used Avail Use% Mounted on
/dev/sda1       457G  123G  311G  29% /
/dev/sda2       1.8T  856G  849G  51% /home

Show Disk Usage with SI Units:

df -H

Display Inode Usage:

df -i

Example Output:

Filesystem      Inodes  IUsed   IFree IUse% Mounted on
/dev/sda1      30474240 456789 30017451    2% /

Partition Information

List All Partitions

Display partition table:

sudo fdisk -l

Example Output:

Disk /dev/sda: 465.76 GiB, 500107862016 bytes, 976773168 sectors
Device     Boot   Start       End   Sectors   Size Id Type
/dev/sda1  *       2048 976771071 976769024 465.8G 83 Linux

Show Mounted Filesystems:

mount

Display /etc/fstab Configuration:

cat /etc/fstab

Disk Block Devices

Gather Disk Information

List block devices:

lsblk

Example Output:

NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda      8:0    0 465.8G  0 disk
├─sda1   8:1    0   512M  0 part /boot/efi
├─sda2   8:2    0   450G  0 part /
└─sda3   8:3    0  15.3G  0 part [SWAP]

Show Filesystem Type:

lsblk -f

Example Output:

NAME   FSTYPE LABEL UUID                                 MOUNTPOINT
sda
├─sda1 vfat         1234-5678                            /boot/efi
├─sda2 ext4         12345678-1234-1234-1234-123456789abc /
└─sda3 swap         87654321-4321-4321-4321-210987654321 [SWAP]

Hardware Information

PCI Devices

List PCI Devices

Display all PCI devices:

lspci

Example Output:

00:00.0 Host bridge: Intel Corporation Coffee Lake HOST and DRAM Controller (rev 0c)
00:02.0 VGA compatible controller: Intel Corporation WhiskeyLake-U GT2 [UHD Graphics 620] (rev 02)
00:04.0 Signal processing controller: Intel Corporation Xeon E3-1200 v5/E3-1500 v5/6th Gen Core Processor Thermal Subsystem (rev 0c)
00:08.0 System peripheral: Intel Corporation Xeon E3-1200 v5/v6 / E3-1500 v5 / 6th/7th/8th Gen Core Processor Gaussian Mixture Model
00:12.0 Signal processing controller: Intel Corporation Cannon Point-LP Thermal Controller (rev 30)
00:14.0 USB controller: Intel Corporation Cannon Point-LP USB 3.1 xHCI Controller (rev 30)
00:14.2 RAM memory: Intel Corporation Cannon Point-LP Shared SRAM (rev 30)
00:14.3 Network controller: Intel Corporation Cannon Point-LP CNVi [Wireless-AC] (rev 30)
00:15.0 Serial bus controller: Intel Corporation Cannon Point-LP Serial IO I2C Controller #0 (rev 30)
00:15.1 Serial bus controller: Intel Corporation Cannon Point-LP Serial IO I2C Controller #1 (rev 30)
00:16.0 Communication controller: Intel Corporation Cannon Point-LP MEI Controller #1 (rev 30)
00:16.3 Serial controller: Intel Corporation Cannon Point-LP Keyboard and Text (KT) Redirection (rev 30)
00:19.0 Serial bus controller: Intel Corporation Cannon Point-LP Serial IO I2C Host Controller (rev 30)
00:1c.0 PCI bridge: Intel Corporation Cannon Point-LP PCI Express Root Port #1 (rev f0)
00:1c.4 PCI bridge: Intel Corporation Cannon Point-LP PCI Express Root Port #5 (rev f0)
00:1d.0 PCI bridge: Intel Corporation Cannon Point-LP PCI Express Root Port #13 (rev f0)
00:1f.0 ISA bridge: Intel Corporation Cannon Point-LP LPC Controller (rev 30)
00:1f.3 Audio device: Intel Corporation Cannon Point-LP High Definition Audio Controller (rev 30)
00:1f.4 SMBus: Intel Corporation Cannon Point-LP SMBus Controller (rev 30)
00:1f.5 Serial bus controller: Intel Corporation Cannon Point-LP SPI Controller (rev 30)
00:1f.6 Ethernet controller: Intel Corporation Ethernet Connection (6) I219-LM (rev 30)
01:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. RTS525A PCI Express Card Reader (rev 01)
02:00.0 PCI bridge: Intel Corporation JHL6340 Thunderbolt 3 Bridge (C step) [Alpine Ridge 2C 2016] (rev 02)
03:00.0 PCI bridge: Intel Corporation JHL6340 Thunderbolt 3 Bridge (C step) [Alpine Ridge 2C 2016] (rev 02)
03:01.0 PCI bridge: Intel Corporation JHL6340 Thunderbolt 3 Bridge (C step) [Alpine Ridge 2C 2016] (rev 02)
03:02.0 PCI bridge: Intel Corporation JHL6340 Thunderbolt 3 Bridge (C step) [Alpine Ridge 2C 2016] (rev 02)
04:00.0 System peripheral: Intel Corporation JHL6340 Thunderbolt 3 NHI (C step) [Alpine Ridge 2C 2016] (rev 02)
3a:00.0 USB controller: Intel Corporation JHL6340 Thunderbolt 3 USB 3.1 Controller (C step) [Alpine Ridge 2C 2016] (rev 02)
3b:00.0 Non-Volatile memory controller: MAXIO Technology (Hangzhou) Ltd. NVMe SSD Controller MAP1202 (rev 01)

Detailed PCI Information:

lspci -v

Show Specific Device (e.g., Network):

lspci | grep -i network

USB Devices

List USB Devices

Display all USB devices:

lsusb

Example Output:

Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 004: ID 0a5c:5842 Broadcom Corp. 58200
Bus 001 Device 003: ID 0c45:6a09 Microdia Integrated_Webcam_HD
Bus 001 Device 002: ID 046d:c077 Logitech, Inc. M105 Optical Mouse
Bus 001 Device 005: ID 8087:0aaa Intel Corp. Bluetooth 9460/9560 Jefferson Peak (JfP)
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

Detailed USB Information:

lsusb -v

Show USB Device Tree:

lsusb -t

All Hardware Information

Using inxi

Display comprehensive hardware information:

inxi -Fxz

Note

Install inxi if not available: sudo apt install inxi

Using hwinfo

Show short hardware summary:

hwinfo --short

Detailed Hardware Information:

hwinfo

Note

Install hwinfo if not available: sudo apt install hwinfo

Using lshw

Display hardware information in short format:

lshw -short

Detailed Hardware Listing:

sudo lshw

Output to HTML File:

sudo lshw -html > hardware.html

Using lsdev

List all device drivers:

lsdev

Note

Install lsdev if not available: sudo apt install procinfo

Using dmidecode

Get all DMI/SMBIOS information:

sudo dmidecode

Save System Information to File:

sudo dmidecode > systeminfo.txt

System Status and Monitoring

System Uptime

Display System Uptime

Show how long the system has been running:

uptime

Example Output:

18:08:34 up 2 days,  7:30,  1 user,  load average: 0.67, 0.80, 1.28

Pretty Uptime Format:

uptime -p

Example Output:

up 2 days, 7 hours, 30 minutes

Date and Time

Display Current Date and Time:

date

Example Output:

Wednesday 29 October 2025 06:09:17 PM IST

Show Date in Specific Format:

date '+%Y-%m-%d %H:%M:%S'

Example Output:

2025-10-29 18:09:33

User Information

Show Current User:

whoami

Example Output:

john

Show Current User’s Groups:

groups

Example Output:

logicrays adm cdrom sudo dip plugdev lpadmin sambashare www-data docker

Show Who is Logged In:

who

Example Output:

john     pts/0        2025-10-29 10:15 (192.168.1.100)
jane     pts/1        2025-10-29 12:30 (192.168.1.105)

Show Last Logged In Users:

last

Show Login History:

lastlog

Process Information

View Running Processes

Show Running Processes (Interactive):

top

Take One Snapshot:

top -n 1

Show All Processes:

ps aux

Top 10 Memory-Consuming Processes:

ps aux --sort=-%mem | head -10

Example Output:

USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
mysql     1234  2.5 15.3 2847564 2456432 ?     Ssl  Oct28  23:15 /usr/sbin/mysqld
www-data  5678  1.8 8.2  1234567 1312456 ?     S    Oct28  15:42 php-fpm: pool www

Top 10 CPU-Consuming Processes:

ps aux --sort=-%cpu | head -10

Network Information

Network Interfaces

Show All Network Interfaces

Display IP addresses and network interfaces:

ip a

or:

ip address show

Example Output:

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536
    inet 127.0.0.1/8 scope host lo
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500
    inet 192.168.1.100/24 brd 192.168.1.255 scope global eth0

Show Specific Interface:

ip a show eth0

Show Only IP Addresses:

hostname -I

Network Connections

Show Open Ports and Connections

Display all TCP and UDP listening ports:

ss -tuln

Example Output:

Netid State  Recv-Q Send-Q Local Address:Port  Peer Address:Port
tcp   LISTEN 0      128    0.0.0.0:22           0.0.0.0:*
tcp   LISTEN 0      80     0.0.0.0:80           0.0.0.0:*
tcp   LISTEN 0      128    0.0.0.0:443          0.0.0.0:*

Show All Connections:

ss -tuna

Alternative: Using netstat:

netstat -tuln

Note

Install net-tools if netstat is not available: sudo apt install net-tools

Routing Information

Show Routing Table:

ip r

or:

ip route show

Example Output:

default via 192.168.1.1 dev eth0 proto dhcp metric 100
192.168.1.0/24 dev eth0 proto kernel scope link src 192.168.1.100

Show Default Gateway:

ip route | grep default

Kernel and Module Information

Kernel Information

Display Kernel Version:

uname -r

Example Output:

5.15.0-157-generic

Show Kernel Details:

uname -a

Kernel Modules

List Loaded Kernel Modules:

lsmod

Example Output:

Module                  Size  Used by
btrfs                1392640  0
xor                    24576  1 btrfs
raid6_pq              114688  1 btrfs

Show Specific Module Information:

modinfo module_name

Example:

modinfo e1000e

Kernel Messages

View Last Kernel Messages:

dmesg | tail -20

View All Kernel Messages:

dmesg

Search Kernel Messages:

dmesg | grep -i error

System Logs

View System Logs

View Recent System Logs

Show last 20 system log entries:

journalctl -n 20

Follow System Logs in Real-Time:

journalctl -f

View Logs Since Boot:

journalctl -b

View Logs for Specific Service:

journalctl -u apache2

View Logs for Specific Time Range:

journalctl --since "2025-10-29 10:00:00" --until "2025-10-29 12:00:00"

View Logs with Priority

Show only error messages:

journalctl -p err

Environment and Configuration

Environment Variables

Display All Environment Variables:

env

Show Specific Variable:

echo $PATH

Example Output:

/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin

Display Shell Variables:

set

System Configuration Files

View Important Configuration Files

• /etc/os-release - OS information

• /etc/hostname - System hostname

• /etc/hosts - Host name mapping

• /etc/fstab - Filesystem mount configuration

• /etc/network/interfaces - Network configuration (Debian/Ubuntu)

• /etc/resolv.conf - DNS configuration

System Information Script

Interactive System Information Tool

For convenient access to all these system information commands, use the check_system bash script.

See also

For installation instructions and the complete script, see Script 7: System Information Checker

The automated script provides:

• Interactive menu with 38+ checking options

• Color-coded output for better readability

• Architecture and current user detection

• Organized command categories (System, CPU, Memory, Disk, Network, Hardware, Logs)

• Report generation with timestamp

• Help documentation

Quick Example

After installing the script from the bash service scripts guide:

check_system

The script will display an interactive menu where you can select from 38+ options to view different system information.

Example Output:

------------------------------------
✅ Current System Architecture: x86_64

👤 Current Logged In User: john
------------------------------------
Please select an option:
[0] General system info - [uname -a]
[1] Check host name - [hostname]
[2] Linux OS info - [cat /etc/os-release]
...
[37] OS type - [uname -o]
[q] Quit

Enter your choice:

Quick Reference

Essential Commands

System Information:

uname -a                  # Complete system info
hostname                  # System hostname
hostnamectl               # Detailed hostname info
cat /etc/os-release       # OS details
uname -m                  # System architecture
getconf LONG_BIT          # 32 or 64 bit

CPU:

lscpu                     # CPU information
nproc                     # Number of processors
cat /proc/cpuinfo         # Detailed CPU info

Memory:

free -h                   # Memory usage
cat /proc/meminfo         # Detailed memory info
sudo dmidecode -t memory  # Memory hardware info

Disk:

df -h                     # Disk usage
lsblk                     # Block devices
sudo fdisk -l             # Partition information
df -i                     # Inode usage

Hardware:

lspci                     # PCI devices
lsusb                     # USB devices
lshw -short               # Hardware summary
sudo dmidecode            # DMI/SMBIOS info

Network:

ip a                      # Network interfaces
ss -tuln                  # Open ports
ip r                      # Routing table
hostname -I               # IP addresses

System Status:

uptime                    # System uptime
top                       # Process monitor
who                       # Logged in users
ps aux                    # All processes

Logs:

journalctl -n 20          # Recent logs
dmesg | tail -20          # Kernel messages

Common Use Cases

Server Inventory

Collect complete server specifications:

echo "=== Server Inventory ===" > server_info.txt
echo "Hostname: $(hostname)" >> server_info.txt
echo "OS: $(cat /etc/os-release | grep PRETTY_NAME | cut -d'"' -f2)" >> server_info.txt
echo "Kernel: $(uname -r)" >> server_info.txt
echo "CPU: $(lscpu | grep 'Model name' | cut -d':' -f2 | xargs)" >> server_info.txt
echo "Memory: $(free -h | grep Mem | awk '{print $2}')" >> server_info.txt
echo "Disk: $(df -h / | tail -1 | awk '{print $2}')" >> server_info.txt
cat server_info.txt

Performance Monitoring

Check system performance metrics:

echo "CPU Usage:"
top -bn1 | grep "Cpu(s)" | awk '{print $2}' | cut -d'%' -f1

echo "Memory Usage:"
free | grep Mem | awk '{printf("%.2f%%\n", $3/$2 * 100.0)}'

echo "Disk Usage:"
df -h / | tail -1 | awk '{print $5}'

Troubleshooting

Gather diagnostic information:

echo "System Diagnostics" > diagnostics.txt
echo "==================" >> diagnostics.txt
echo "" >> diagnostics.txt
echo "Uptime:" >> diagnostics.txt
uptime >> diagnostics.txt
echo "" >> diagnostics.txt
echo "Top Memory Processes:" >> diagnostics.txt
ps aux --sort=-%mem | head -6 >> diagnostics.txt
echo "" >> diagnostics.txt
echo "Recent Errors:" >> diagnostics.txt
journalctl -p err -n 10 >> diagnostics.txt

Resources

Official Documentation

• Linux Man Pages: https://linux.die.net/man/

• Ubuntu Documentation: https://help.ubuntu.com/

• Red Hat System Administration: https://www.redhat.com/sysadmin/

Useful Tutorials

• TecMint: https://www.tecmint.com/commands-to-collect-system-and-hardware-information-in-linux/

• Red Hat SysAdmin: https://www.redhat.com/sysadmin/linux-system-info-commands

• Baeldung Linux: https://www.baeldung.com/linux/cli-hardware-info

• Opensource.com: https://opensource.com/article/19/9/linux-commands-hardware-information

Related Guides

• Linux: Commands Reference Guide - General Linux command reference

• Linux: Package Management Guide - Linux package management

• LAMP Stack Installation Guide - LAMP stack setup

Best Practices

Regular Monitoring

1. Check system resources regularly: Monitor CPU, memory, and disk usage

2. Review logs periodically: Check for errors and warnings

3. Document your system: Keep hardware and software inventory updated

4. Monitor performance trends: Track resource usage over time

5. Set up alerts: Use monitoring tools for proactive issue detection

Security Considerations

1. Limit information exposure: Don’t share detailed system info publicly

2. Secure sensitive files: Protect configuration and log files

3. Monitor unauthorized access: Check who commands and logs

4. Regular audits: Review system users and processes

5. Keep systems updated: Apply security patches promptly

Warning

Some commands like dmidecode, fdisk, and lshw require root/sudo access and may expose sensitive hardware information. Use caution when sharing output from these commands.

Conclusion

Understanding how to gather system information is fundamental for Linux system administration. The commands and tools covered in this guide provide comprehensive insights into your system’s hardware, software, and performance characteristics.

Key takeaways:

• Use appropriate commands for specific information needs

• Combine commands to create useful reports

• Automate information gathering with scripts

• Monitor systems regularly for optimal performance

• Keep documentation updated with system changes

The provided check_system script offers a convenient way to access all major system information commands through an interactive menu, making system administration tasks more efficient.