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Linux - Fundamental: System Information

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Linux - Fundamental: System Information

Linux Distro

Linux Distributions
- Linux Kernel + Additional software/application
- Each has its own focus
- distro / flavor
  - short for distributions
  - https://distrowatch.com/

Debian-based Distributions

Originates from the Debian Project, one of the oldest and most influential Linux distributions.
Key Features:
- Uses .deb packages and the APT (Advanced Package Tool) system.
Popular Distributions
- Debian:
  - The upstream distribution, emphasizing free software and stability.
- Ubuntu:
  - User-friendly, widely adopted for desktops, servers, and cloud environments.
- Linux Mint:
  - Aimed at beginners, based on Ubuntu or directly on Debian.
- Kali Linux:
  - Based on Debian, tailored for penetration testing and security analysis.

Red Hat-based Distributions

Originates from Red Hat Linux, a commercial distribution focused on enterprise environments.
Key Features: Uses .rpm packages and tools like YUM or DNF.
Enterprise Focus: Offers features tailored for servers, virtualization, and cloud computing.
Popular Distributions
- Red Hat Enterprise Linux (RHEL):
  - A commercial distribution with professional support.
- Fedora:
  - A cutting-edge, community-driven distribution, often serving as a testing ground for RHEL.
- CentOS/AlmaLinux/Rocky Linux:
  - Community-supported alternatives to RHEL, compatible for enterprise use.
- Oracle Linux:
  - Supported by Oracle. Aims to be fully compatible with Red Hat Enterprise Linux.

Arch-based Distributions

Originates from Arch Linux, a minimalist and lightweight distribution that emphasizes simplicity and user control.
Key Features:
- Package Management:
  - Uses the pacman package manager and supports the Arch User Repository (AUR).
- Rolling Release:
  - Always up-to-date without major version upgrades.
- Manual Setup: - Requires users to configure most aspects, providing a deeper understanding of Linux.
Popular Distributions
- Arch Linux:
  - The original, requiring manual installation and configuration.
- Manjaro:
  - A user-friendly version of Arch Linux with preconfigured tools and graphical interfaces.
- EndeavourOS: A lightweight, beginner-friendly Arch-based distribution.

SUSE-based Distributions

Originates from SUSE Linux, a German distribution focused on enterprise environments and ease of use.
Key Features
- Package Management:
  - Uses .rpm packages with the zypper package manager.
- Enterprise Tools:
  - Includes tools like YaST (Yet another Setup Tool) for system administration.
Popular Distributions
- openSUSE Leap: Stable, fixed-release version ideal for production use.
- openSUSE Tumbleweed: Rolling release version for users who want the latest software.
- SUSE Linux Enterprise (SLE): A commercial distribution with professional support.

Others

Alpine Linux:
- Minimalist and security-focused, widely used in containerized environments like Docker.

Method: Identifying Linux Distro

Identifying the flavor (distribution) of Linux is important:
- Package Management and Software Installation
  - Debian-based (Ubuntu, Debian, etc.): Use apt with .deb packages.
  - Red Hat-based (RHEL, CentOS, AlmaLinux, etc.): Use yum or dnf with .rpm packages.
  - SUSE-based: Use zypper.
- Configuration File Locations and System Tools
  - Network:
    - Ubuntu:/etc/network/interfaces
    - RHEL: /etc/sysconfig/network-scripts/
  - System Tools:
    - YaST (SUSE) or firewalld (RHEL)

Check /etc/os-release File
- Most modern Linux distributions include the /etc/os-release file, which provides detailed information about the operating system.
Distribution-Specific Files
- /etc/redhat-release or /etc/centos-release: Red Hat-based (RHEL, CentOS, AlmaLinux, etc.)
- /etc/debian_version: Debian-based (Debian, Ubuntu, etc.)
Command:
- uname -a: provides information about a Linux system’s operating system and hardware platform
- hostnamectl: provides information about the operating system and the hostname.

Lab: Get Linux Distro

`/etc/os-release` File

# rhel8
cat /etc/os-release
# NAME="Red Hat Enterprise Linux"
# VERSION="8.10 (Ootpa)"
# ID="rhel"
# ID_LIKE="fedora"
# VERSION_ID="8.10"
# PLATFORM_ID="platform:el8"
# PRETTY_NAME="Red Hat Enterprise Linux 8.10 (Ootpa)"
# ANSI_COLOR="0;31"
# CPE_NAME="cpe:/o:redhat:enterprise_linux:8::baseos"
# HOME_URL="https://www.redhat.com/"
# DOCUMENTATION_URL="https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8"
# BUG_REPORT_URL="https://issues.redhat.com/"

# REDHAT_BUGZILLA_PRODUCT="Red Hat Enterprise Linux 8"
# REDHAT_BUGZILLA_PRODUCT_VERSION=8.10
# REDHAT_SUPPORT_PRODUCT="Red Hat Enterprise Linux"
# REDHAT_SUPPORT_PRODUCT_VERSION="8.10"

# kali
cat /etc/os-release
# PRETTY_NAME="Kali GNU/Linux Rolling"
# NAME="Kali GNU/Linux"
# VERSION_ID="2024.3"
# VERSION="2024.3"
# VERSION_CODENAME=kali-rolling
# ID=kali
# ID_LIKE=debian
# HOME_URL="https://www.kali.org/"
# SUPPORT_URL="https://forums.kali.org/"
# BUG_REPORT_URL="https://bugs.kali.org/"
# ANSI_COLOR="1;31"

# Ubuntu
cat /etc/os-release
# PRETTY_NAME="Ubuntu 24.04.1 LTS"
# NAME="Ubuntu"
# VERSION_ID="24.04"
# VERSION="24.04.1 LTS (Noble Numbat)"
# VERSION_CODENAME=noble
# ID=ubuntu
# ID_LIKE=debian
# HOME_URL="https://www.ubuntu.com/"
# SUPPORT_URL="https://help.ubuntu.com/"
# BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
# PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
# UBUNTU_CODENAME=noble
# LOGO=ubuntu-logo

Command `uname -a`

# rhel
uname -a
# Linux serverhost 4.18.0-553.30.1.el8_10.x86_64 #1 SMP Fri Nov 15 03:46:25 EST 2024 x86_64 x86_64 x86_64 GNU/Linux

# kali
uname -a
# Linux kali 6.8.11-amd64 #1 SMP PREEMPT_DYNAMIC Kali 6.8.11-1kali2 (2024-05-30) x86_64 GNU/Linux

# Ubuntu
uname -a
# Linux ubuntuhost 6.8.0-50-generic #51-Ubuntu SMP PREEMPT_DYNAMIC Sat Nov  9 17:58:29 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux

Command `hostnamectl`

# rhel
hostnamectl
  #  Static hostname: serverhost
  #        Icon name: computer-vm
  #          Chassis: vm
  #       Machine ID: ca299475723c4510bf96994f9b0391d6
  #          Boot ID: d2b092c72847419299d28371039f322b
  #   Virtualization: vmware
  # Operating System: Red Hat Enterprise Linux 8.10 (Ootpa)
  #      CPE OS Name: cpe:/o:redhat:enterprise_linux:8::baseos
  #           Kernel: Linux 4.18.0-553.30.1.el8_10.x86_64
  #     Architecture: x86-64

# kali
hostnamectl
#  Static hostname: kali
#        Icon name: computer-vm
#          Chassis: vm 🖴
#       Machine ID: 30e662c5c81d4191bd2444a79c97d2e0
#          Boot ID: e71d7023d146411b8f35e5febc4b0f97
#     AF_VSOCK CID: 2318294775
#   Virtualization: vmware
# Operating System: Kali GNU/Linux Rolling
#           Kernel: Linux 6.8.11-amd64
#     Architecture: x86-64
#  Hardware Vendor: VMware, Inc.
#   Hardware Model: VMware Virtual Platform
# Firmware Version: 6.00
#    Firmware Date: Thu 2020-11-12
#     Firmware Age: 4y 1month 3d

# Ubuntu
hostnamectl
#  Static hostname: ubuntuhost
#        Icon name: computer-vm
#          Chassis: vm 🖴
#       Machine ID: f03cfca8f1fd42509cb87977b8ba9444
#          Boot ID: ec79fc9686df4b16878786c1edbf1370
#   Virtualization: vmware
# Operating System: Ubuntu 24.04.1 LTS
#           Kernel: Linux 6.8.0-50-generic
#     Architecture: x86-64
#  Hardware Vendor: VMware, Inc.
#   Hardware Model: VMware Virtual Platform
# Firmware Version: 6.00
#    Firmware Date: Thu 2020-11-12
#     Firmware Age: 4y 1month 3d

System Information

Command	Description
`tty`	Display current active terminal session file
`uptime`	how long the system has been running
`uptime -p`	show uptime in pretty format
`uptime -s`	system up since
`hostnamectl`	Query the system hostname
`date`
`date -s`
`uname`	Display system information
`uname -a`	Display all information
`uname -s`	Display the kernel name
`uname -p`	Display the processor type
`lscpu`	Display information about the CPU architecture

Lab: System information

Session file and uptime

tty
# /dev/pts/1

uptime
#  18:23:11 up  2:13,  4 users,  load average: 0.00, 0.00, 0.00

uptime -p
# up 2 hours, 13 minutes

uptime:

current system time: 18:23:11

up duration: 2:13

number of logged-in users: 4 users

CPU load averages over the past 1, 5, and 15 minutes: 0.00, 0.00, 0.00

System information

uname
# Linux

uname -a
# Linux localhost.localdomain 5.14.0-503.22.1.el9_5.x86_64 #1 SMP PREEMPT_DYNAMIC Wed Jan 15 08:02:15 EST 2025 x86_64 x86_64 x86_64 GNU/Linux

uname -p
# x86_64

CPU

lscpu
# Architecture:             x86_64
#   CPU op-mode(s):         32-bit, 64-bit
#   Address sizes:          45 bits physical, 48 bits virtual
#   Byte Order:             Little Endian
# CPU(s):                   2
#   On-line CPU(s) list:    0,1
# Vendor ID:                GenuineIntel
#   BIOS Vendor ID:         GenuineIntel
#   Model name:             Intel(R) Core(TM) 5 120U
#     BIOS Model name:      Intel(R) Core(TM) 5 120U
#     CPU family:           6
#     Model:                186
#     Thread(s) per core:   1
#     Core(s) per socket:   1
#     Socket(s):            2
#     Stepping:             3
#     BogoMIPS:             4991.99
#     Flags:                fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36
#                           clflush mmx fxsr sse sse2 ss syscall nx pdpe1gb rdtscp lm constant_tsc a
#                           rch_perfmon rep_good nopl xtopology tsc_reliable nonstop_tsc cpuid tsc_k
#                           nown_freq pni pclmulqdq ssse3 fma cx16 sse4_1 sse4_2 x2apic movbe popcnt
#                            aes xsave avx f16c rdrand hypervisor lahf_lm abm 3dnowprefetch pti ssbd
#                            ibrs ibpb stibp fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid rd
#                           seed adx smap clflushopt clwb sha_ni xsaveopt xsavec xgetbv1 xsaves avx_
#                           vnni arat umip gfni vaes vpclmulqdq rdpid movdiri movdir64b fsrm md_clea
#                           r serialize flush_l1d arch_capabilities
# Virtualization features:
#   Hypervisor vendor:      VMware
#   Virtualization type:    full
# Caches (sum of all):
#   L1d:                    96 KiB (2 instances)
#   L1i:                    64 KiB (2 instances)
#   L2:                     2.5 MiB (2 instances)
#   L3:                     24 MiB (2 instances)
# NUMA:
#   NUMA node(s):           1
#   NUMA node0 CPU(s):      0,1
# Vulnerabilities:
#   Gather data sampling:   Not affected
#   Itlb multihit:          Not affected
#   L1tf:                   Mitigation; PTE Inversion
#   Mds:                    Mitigation; Clear CPU buffers; SMT Host state unknown
#   Meltdown:               Mitigation; PTI
#   Mmio stale data:        Unknown: No mitigations
#   Reg file data sampling: Vulnerable: No microcode
#   Retbleed:               Mitigation; IBRS
#   Spec rstack overflow:   Not affected
#   Spec store bypass:      Mitigation; Speculative Store Bypass disabled via prctl
#   Spectre v1:             Mitigation; usercopy/swapgs barriers and __user pointer sanitization
#   Spectre v2:             Mitigation; IBRS; IBPB conditional; STIBP disabled; RSB filling; PBRSB-e
#                           IBRS Not affected; BHI SW loop, KVM SW loop
#   Srbds:                  Not affected
#   Tsx async abort:        Not affected

Note_Tech

Linux - Fundamental: System Information

Linux Distro

Debian-based Distributions

Red Hat-based Distributions

Arch-based Distributions

SUSE-based Distributions

Others

Method: Identifying Linux Distro

Lab: Get Linux Distro

/etc/os-release File

Command uname -a

Command hostnamectl

System Information

Lab: System information

Session file and uptime

System information

CPU

`/etc/os-release` File

Command `uname -a`

Command `hostnamectl`