Thursday, December 11, 2014

Various commands to get Hardware and Software information from the system:

 Various commands to get Hardware information from the system:

On Linux based system most of the hardware information can be extracted from /proc
Example display CPU information:

# cat /proc/cpuinfo

# lscpu

Example display Memory information:

# cat /proc/meminfo

# free

# free –m (check man free for more info) 

Various commands to get Software information from the system:

# cat /proc/version
# uname –a
lsb_release –a
# cat /etc/redhat-release
# rpm qa

Wednesday, December 10, 2014

Keyboard Setting on Linux Redhat


I. To change keyboard language:

There is 2 ways to change your keyboard language on Redhat System

1. Persistent change

#vi /etc/sysconfig/keyboard 
KEYTABLE="fr"
MODEL="pc105+inet"
LAYOUT="fr"
KEYBOARDTYPE="pc
you can change it by editing "fr" to "us" or what ever... 

#system-config-keyboard

2. Temporary change

#setxkbmap fr 


Friday, December 5, 2014

Archiving with Tar


Tar files place several files or the contents of a directory or directories in one file


tar -cvf filename.tar files/directories

To list the contents of a tar file, type: 

#tar -tvf test.tar


To extract the contents of a tar file, type:  

#tar -xvf test.tar


The tar command does not compress files automatically. 

You can compress tar files with:

#tar -czvf test.tar


Compressed tar files are conventionally given the extension .tgz and are compressed with gzip.
To expand a compressed tar file type:

#tar -xzvf test.tgz


Wednesday, December 3, 2014

Compressing with Gzip and Zip

Compressed files use less disk space and download faster than large, uncompressed files.

To compress a file,
# gzip filename.ext

The file will be compressed and saved as filename.ext.gz.

To expand a compressed file, type:
#gunzip filename.ext.gz

To compress a file with zip, type the following:
#zip -r filename.zip files

To extract the contents of a zip file, type:
#unzip filename.zip

Monday, June 2, 2014

Why Linux dominates the server world





Today Linux is present in a myriad of devices around us, from smartphones to game consoles, but is even closer than we think.


So do not use any of these devices, by simply opening a web page we are already using Linux . The reason? Because Linux has become the most used operating system in the server and not by accident. Let’s look at its main advantages.

Stability

No one doubts the stability of a Linux system, especially when it is well known that a typical installation can run for years without failure . Linux handles large amounts of much better than Windows processes and requires restart before configuration changes or after system updates. Windows degrades over time and from time to time require user intervention to defragment your hard disk, clean up registry or applying any other gadget that allows restore some flexibility to the system. In Linux, with a good file system (as Ext4 or XFS) you never hear the word defrag.

Security

No system is immune to the attacks, but the speed of response to a fault and the amount of people who can audit it definitely makes a difference. Microsoft reacts more slowly to security holes in Windows and this leaves their systems vulnerable for longer. The Linux community responds much faster to these events and thanks to that source code is available, anyone with the knowledge can correct this and make it available to users immediately. It is worth to say that Linux is much less frequently attacked by virus andmalware .

Management applications

Linux distributions use the official repositories for their applications, applying quality control and security policies that ensure the integrity and health of installed packages. And not just about security and integrity is also an issue of usability because everything we need is in one place .

Flexibility

A Linux installation can be adjusted as necessary . It is common not to install GUI to avoid wasting RAM, choose optimal system files according to the needs of the service or build an application if we adapt to fit our system. Linux can be reconfigured to include only essential services for the type of business and optimize the use of resources.

Costs

Linux is the undisputed king in implementation costs and can hardly be overthrown. Even with corporate support enterprise versions are cheaper than Windows or other software owner. This is because most of the software used in Linux is free while the owner is tied to expensive licensing schemes or sales of additional plugins to add new functionality.

Community

Linux is and has always been a community , this makes developers are always hearing you say and your users need. This joint effort allows most of the distributions can post updates every 6 months, things happens much less often on the side of Windows.

Freedom

Perhaps the most philosophical of all the advantages, but is that Linux does not have behind you no limiting yourself company using the system or enclose dimly legal clauses. With Linux are free to use, modify and combine what you want to meet your needs .
Among the most used server distributions are Debian, Slackware, CentOS and Red Hat Enterprise Linux.Unsure about what? Operating system to use for your server? Try it and tell us how you do, you certainly will not regret it.

Thursday, January 23, 2014

See how Openshift works!

 Understanding OpenShift Web site
  https://www.openshift.com/walkthrough/how-it-works

OpenShift is a next-generation cloud application platform that makes it easy to develop, deploy, and scale applications in the cloud – public or private.








INFASTRUCTURE



PAAS (Platform as a Service)

























SElinux



Wednesday, January 8, 2014

Setting Up Linux Networking



Most of the networkConfiguration is kept in files; therefore, adjusting these settings is simple.
To start, you can use three management commands:
When you’re working with network interfaces, there are two additional files you need to know:
ifconfig                       Displays the IP address and other interface-related information
route                          Enables you to view or change the routing information on the system
system-config-network                  Provides a menu-driven utility for network configuration tui
/etc/sysconfig/network                 This file contains gateway and hostname information.
/etc/sysconfig/network-scripts      This directory contains all the interface config files for your system.

# cat /etc/sysconfig/network
NETWORKING=yes
NETWORKING_IPV6=yes
HOSTNAME=RHEL01


# cat /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
BOOTPROTO=dhcp
HWADDR=08:00:27:30:74:AA
ONBOOT=yes
DHCP_HOSTNAME=RHEL01
TYPE=Ethernet


Interface details can be edited:
Step 1. To bring the single interface down, use ifdown:
# ifdown eth1
Step 2. To restore the interface that you just brought down, use ifup:
# ifup eth1
Use the ifconfig command to display your current IP address

Syntax: ifconfig [options] [interface]

Options:

netmask             MASK Specifies the netmask for the interface
hw ADDRESS        Sets the MAC address of the interface
up                     Brings up the interface
down                    Bring down the interface

Shutting down interface eth0:                                 [ OK ]
Shutting down interface eth1:                                 [ OK ]
Shutting down loopback interface:                          [ OK ]
Bringing up loopback interface:                               [ OK ]
Bringing up interface eth0:
Determining IP information for eth0... done.          [ OK ]

Bringing up interface eth1:                                       [ OK ]