chmod Quick Referance with Examples

What is chmod ?

chmod ( Change Mode ) is a command line utility in Unix , Linux and other Unix like systems to change the read, write, execute permissions of a file for owner , group and others.

How to use chmod?

Chmod command is used in two ways :
1. Using octal value & position : Sets the permission for owner, group and others with octal values , 4 for read , 2 for write , 1 for execute and any sum of these number to get cumulative permissions.

SHA-1 Collision – Insecurity of SHA-1 exposed by Google

SHA-1 is widely used in applications like SSL, SSH, TLS, IPsec PGP, S/MIME to protect the sensitive information.

Google has demonstrated that SHA-1 Collision is possible and two files can have the same SHA-1 hash. This means that system can be manipulated by presenting it with manipulated data with same hash as good data.

man command in Linux and Unix

man command, short for manual, provides help for the commands, utilities or function in Linux and Unix systems. Learn about usage , related packages, sections and other interesting facts about man pages.

Submit Guest Posts

Great News, adminschoice.com is opening up to allow guest posts from bloggers and technical professionals.

If you are a tech blogger or a technical professional  wishing to share your experience and knowledge with others you can contribute to adminschoice.com and establish yourself as technical expert in your field.

Solaris 11 & Solaris 10 Certification

Learn about the Solaris 10 & 11 certification , price, number of questoons , duration and direct links to official site for exam 1z0-876, 1z0-821 and more.

Solaris Network Configuration

Learn Solaris Network configuration for static , dhcp & wifi in Solaris 11 using netadm and ipadmp. Earlier versions are covered towards the end of this document. Continue reading for Solaris 11 & for prior versions, please turn to Page 5 or click here

Download Linux : Top 10 Free Linux Distributions for Desktop and Servers

Here is the list of top 10 Linux distributions to free download latest version of linux operating system with links to linux documentation and home pages.
All the Linux distributions are either derivative of GNU/Linux ( OS made up of Linux Kernel developed by Linus Torvalds and GNU software repository) or derived from other Linux derivatives.

Top 10 Must have Books for Unix and Linux Administartors

Here is the top 10 must have books for system administartors who are starting working in Unix and Linux adminstration or current system administartors who want to improve skills and go deeper to learn and manage Unix and Linux systems.

10 Must Have O’Reilly Books for System Administrators

Published several years ago these O’Reilly books are still useful & relevant for the current and new system administratiors. Although these books may not cover latest version of operating systems yet these explains very well the underlaying technical details and process which have not changed over the years.

MongoDB Ransom Attacks Hit 27000 Systems

MongoDB Ransom Attacks has hit 27,000 Systems in few hours from 12000 impacted servers .

Most of the mongoDB installations are exposed to exploites due to poor default access controls for super users .

Hackers are accessing  MongoDB databaases and then copy and delete data from database running in default, unsecure configuration. In return of data administrators are being asked to pay ransom money by bitcoins.

What is Cloud Computing in Simplest Terms

Cloud Computing is the computing using resources – infrastructure or Software hosted on the internet either by a public cloud provider or hosted privately by local IT group of an organization.

awk Commands, Examples & Meaning

Learn to use awk for text and data extraction, data processing, validation,  generate reports for analysis, automation with with the help of examples of if else , compare & arrays plus regular expressions & built in operational variables, meaning, examples &command syntax.

Application Monitoring

Application monitoring

Application monitoring is a very important aspect of a project but unfortunately not much attention is paid to develop the effective monitoring while the projects are still movingh to completions. Once project is complete & live lack of proper monitoring costs in terms of downtime when support persons are not aware if application is having some problems or application not working at all.

Fedora 22 End of Life

Fedora 22 has reached its end of life for updates and support today on July 19, 2016.

No more updates or security fixes, will be provided for Fedora 22. Fedora 23 will be maintained with updated packages until approximately one month after the release of Fedora 25 ( expected on Nov8 ).

Whats new in IOS 9.3.3, OS X El Capitan v10.11.6

Security issues fixed in IOS 9.3.3  & MAC OS X El Capitan v10.11.6 are released  on July 18, 2016.  These releases are mostly bug fixes in kernel and and other supporting areas to close loop hole  for unauthorized access and running code , cause Denial of service and potential memory corruptions issues.