1. The hostname and uname commands print the hostname of the current system:

        $ hostname

Alternatively, they print the following:

        $ uname -n
        server.example.com

2. The -a option to uname prints details about the Linux kernel version, hardware architecture, and more:

        $ uname -a
        server.example.com 2.6.32-642.11.1.e16.x86_64 #1 SMP Fri Nov 18   
        19:25:05 UTC 2016 x86_64 x86_64 GNU/Linux

3. The -r option limits the report to the kernel release:

        $ uname -r
        2.6.32-642.11.1.e16.x86_64

4. The -m option prints the machine type:

        $ uname -m
        x86_64

5. The /proc/ directory holds information about the system, modules, and running processes. /proc/cpuinfo contains CPU details:

        $ cat /proc/cpuinfo
        processor     : 0
        vendor_id     : GenuineIntel
        cpu family    : 6
        model         : 63
        model name    : Intel(R)Core(TM)i7-5820K CPU @ 3.30GHz
        ...

If the processor has multiple cores, these lines will be repeated n times. To extract only one item of information, use sed. The fifth line contains the processor name:

        $ cat /proc/cpuinfo | sed -n 5p
        Intel(R)CORE(TM)i7-5820K CPU @ 3.3 GHz

6. /proc/meminfo contains information about the memory and current RAM usage:

        $ cat /proc/meminfo
        MemTotal:     32777552 kB
        MemFree:      11895296 kB 
        Buffers:        634628 kB
        ...

The first line of meminfo shows the system's total RAM:

        $ cat /proc/meminfo  | head -1
        MemTotal:        1026096 kB

7. /proc/partitions describes the disk partitions:

        $ cat /proc/partitions
        major minor  #blocks  name
           8        0 976762584 sda
           8        1    512000 sda1
           8        2 976248832 sda2
        ...

 The fdisk program edits a disk's partition table and also reports the current partition table. Run this command as  root:

        $ sudo fdisk -l

8. The lshw and dmidecode applications generate long and complete reports about your system. The report includes information about the motherboard, BIOS, CPU, memory slots, interface slots, disks, and more. These must be run as root. dmidecode is commonly available, but you may need to install lshw:

        $ sudo lshw
        description: Computer
        product: 440BX
        vendor: Intel
        ...

        $ sudo dmidecode
        SMBIOS 2.8 present
        115 structures occupying 4160 bytes.
        Table at 0xDCEE1000.

        BIOS Information
           Vendor: American Megatrends Inc
        ...