Hardware

To see which family the CPU of the current system belongs to, use the arch command:


sysadmin@localhost:~$ arch
x86_64

For more information concerning the CPU, use the lscpu command:


sysadmin@localhost:~$ lscpu
Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                4
On-line CPU(s) list:   0-3
Thread(s) per core:    1
Core(s) per socket:    4
Socket(s):             1
NUMA node(s):          1
Vendor ID:             GenuineIntel

To view the amount of RAM in your system, including the swap space, execute the free command. The free command has a -m option to force the output to be rounded to the nearest megabyte (MB) and a -g option to force the output to be rounded to the nearest gigabyte (GB):


sysadmin@localhost:~$ lspci
00:00.0 Host bridge: Intel Corporation 440BX/ZX/DX - 82443BX/ZX/DX Host bridge (rev 01)
00:01.0 PCI bridge: Intel Corporation 440BX/ZX/DX - 82443BX/ZX/DX AGP bridge (rev 01)

sysadmin@localhost:~$ lsusb
Bus 001 Device 002: ID 0e0f:000b VMware, Inc.

Hard drives are associated with file names (called device files) that are stored in the /dev directory.

IDE (Intelligent Drive Electronics) hard drives begin with hd, while USB, SATA (Serial Advanced Technology Attachment) and SCSI (Small Computer System Interface) hard drives begin with sd.

Each hard drive is then assigned a letter which follows the prefix.

Each partition on a disk is given a unique numeric indicator.


root@localhost:~$ fdisk -l /dev/sda
Disk /dev/sda: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders, total 41943040 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000571a2

⁠⁠ ⁠
   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048    39845887    19921920   83  Linux
/dev/sda2        39847934    41940991     1046529    5  Extended
/dev/sda5        39847936    41940991     1046528   82  Linux swap / Solaris

Directory	Contents
`/`	The base of the structure, or root of the filesystem, this directory unifies all directories regardless of whether they are local partitions, removable devices or network shares
`/bin`	Essential binaries like the `ls`, `cp`, and `rm` commands, and be a part of the root filesystem
`/boot`	Files necessary to boot the system, such as the Linux kernel and associated configuration files
`/dev`	Files that represent hardware devices and other special files, such as the `/dev/null` and `/dev/zero` files
`/etc`	Essential host configurations files such as the `/etc/hosts` or `/etc/passwd` files
`/home`	User home directories
`/lib`	Essential libraries to support the executable files in the `/bin` and `/sbin` directories
`/lib64`	Essential libraries built for a specific architecture. For example, the `/lib64` directory for 64-bit AMD/Intel x86 compatible processors
`/media`	Mount point for removable media mounted automatically
`/mnt`	Mount point for temporarily mounting filesystems manually
`/opt`	Optional third-party software installation location
`/proc`	Virtual filesystem for the kernel to report process information, as well as other information
`/root`	Home directory of the root user
`/sbin`	Essential system binaries primarily used by the root user
`/sys`	Virtual filesystem for information about hardware devices connected to the system
`/srv`	Location where site-specific services may be hosted
`/tmp`	Directory where all users are allowed to create temporary files and that is supposed to be cleared at boot time (but often is not)
`/usr`	Second hierarchyNon-essential files for multi-user use
`/usr/local`	Third hierarchyFiles for software not originating from distribution
`/var`	Fourth hierarchyFiles that change over time
`/var/cache`	Files used for caching application data
`/var/log`	Most log files
`/var/lock`	Lock files for shared resources
`/var/spool`	Spool files for printing and mail
`/var/tmp`	Temporary files to be preserved between reboots

On a CentOS system, the primary configuration file for an IPv4 network interface is the /etc/sysconfig/network-scripts/ifcfg-eth0

On a CentOS system, the primary IPv6 configuration file is the same file where IPv4 configuration is stored

IPV6INIT=yes
DHCPV6C=yes

You also need to add the following setting to the /etc/sysconfig/network file:


NETWORKING_IPV6=yes

The address of the DNS server is stored in the /etc/resolv.conf