System Information

Retrieving and displaying information about the Linux system

hostnamectl

The hostnamectl utility is part of systemd, and it is used to query and change the system hostname. It also displays the Linux distribution and kernel version:

If hostnamectl is executed by itself, without any additional commands / options, it will output the same information as the command hostnamectl status

Sample output:

  Static hostname:  example
         Icon name: computer-laptop
           Chassis: laptop
        Machine ID: af8ce1d394b844fea8c19ea5c6a9bd09
           Boot ID: 15bc3ae7bde842f29c8d925044f232b9
  Operating System: Ubuntu 18.04.2 LTS
            Kernel: Linux 4.15.0-54-generic
      Architecture: x86-64

uname

The uname command displays several system information including, the Linux kernel, processor architecture, name version, and release.

Syntax

uname [OPTIONS]...

The options are as follows:

• -s, (--kernel-name) - Prints the kernel name.

• -n, (--nodename) - Prints the system’s node name (hostname).

• -r, (--kernel-release) - Prints the kernel release.

• -v, (--kernel-version) - Prints the kernel version.

• -m, (--machine) - Prints the name of the machine’s hardware name.

• -p, (--processor) - Prints the architecture of the processor.

• -i, (--hardware-platform) - Prints the hardware platform.

• -o, (--operating-system) - Print the name of the operating system.

• -a, (--all) - Prints all information, except omit -p and -i if unknown.

Sample output:

uname -srm

Linux 4.19.0-9-amd64 x86_64

uptime

uptime gives a one line display of the following information. The current time, how long the system has been running, how many users are currently logged on, and the system load averages for the past 1, 5, and 15 minutes.

Sample output

uptime

 03:35:55 up  2:46,  1 user,  load average: 0.79, 0.62, 0.74

/proc/ folder

The /proc directory contains virtual files with information about the system memory , CPU cores , mounted filesystems , processes, and more.

The numbered directories in /proc correspond to process ids running on the system. The status file in these folders contains detailed information about the process

Use commands cat or less to display contents of these files.

File in /proc/	Contents
/proc/cmdline	shows the parameters passed to the kernel at the time it is started
/proc/cpuinfo	processor information, per core
/proc/meminfo	memory information
/proc/version	kernel information

Sample output:

cat /proc/version

Linux version 4.15.0-54-generic (buildd@lgw01-amd64-014) (gcc version 7.4.0 (Ubuntu 7.4.0-1ubuntu1~18.04.1)) #58-Ubuntu SMP Mon Jun 24 10:55:24 UTC 2019