Category Archives: Basics

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.

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.

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.

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.

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.

Bash in Windows 10 : Ten Facts You Must Know

Bash in Windows 10

Bash in Windows : Learn about top 10 must know facts for use and setting the expectation right. 

cpio ( GNU )

CoPy In Out

Usage: cpio [OPTION…] [destination-directory]
GNU `cpio’ copies files to and from archives

# Copy files named in name-list to the archive
cpio -o < name-list [> archive]
# Extract files from the archive
cpio -i [< archive]
# Copy files named in name-list to destination-directory
cpio -p destination-directory < name-list

Main operation mode:

-i, –extract
Extract files from an archive (run in copy-in
mode) -o, –create Create the archive (run in copy-out mode) -p, –pass-through Run in copy-pass mode

-t, –list Print a table of contents of the input

Operation modifiers valid in any mode:

–block-size=BLOCK-SIZE  Set the I/O block size to BLOCK-SIZE * 512
-B  Set the I/O block size to 5120 bytes
-c  Identical to “-H newc”, use the new (SVR4)
portable format.If you wish the old portable
(ASCII) archive format, use “-H odc” instead.
-C, –io-size=NUMBER  Set the I/O block size to the given NUMBER of
–force-local  Archive file is local, even if its name contains
-f, –nonmatching Only copy files that do not match any of the given patterns
Use this FILE-NAME instead of standard input or output. Optional USER and HOST specify the user and host names in case of a remote archive
-H, –format=FORMAT  Use given archive FORMAT
-M, –message=STRING  Print STRING when the end of a volume of the
backup media is reached
-n, –numeric-uid-gid In the verbose table of contents listing, show
numeric UID and GID
–quiet  Do not print the number of blocks copied
–rsh-command=COMMAND  Use remote COMMAND instead of rsh
-v, –verbose  Verbosely list the files processed
-V, –dot  Print a “.” for each file processed
-W, –warning=FLAG  Control warning display. Currently FLAG is one of
‘none’, ‘truncate’, ‘all’. Multiple options

Operation modifiers valid only in copy-in mode:

-b, –swap  Swap both halfwords of words and bytes of
halfwords in the data. Equivalent to -sS
-r, –rename  Interactively rename files
-s, –swapbytes Swap the bytes of each halfword in the files
-S, –swap-halfwords  Swap the halfwords of each word (4 bytes) in the
–to-stdout  Extract files to standard output

-E, –pattern-file=FILE  Read additional patterns specifying filenames to
extract or list from FILE
–only-verify-crc  When reading a CRC format archive, only verify the
checksum of each file in the archive, don’t
actually extract the files

Operation modifiers valid only in copy-out mode:

-A, –append  Append to an existing archive.
-O [[USER@]HOST:]FILE-NAME Archive filename to use instead of standard  output. Optional USER and HOST specify the user and host names in case of a remote archive

Operation modifiers valid only in copy-pass mode:

-l, –link  Link files instead of copying them, when

Operation modifiers valid in copy-in and copy-out modes:

–absolute-filenames  Do not strip file system prefix components from
the file names
–no-absolute-filenames  Create all files relative to the current

Operation modifiers valid in copy-out and copy-pass modes:

-0, –null  A list of filenames is terminated by a null
character instead of a newline
-a, –reset-access-time  Reset the access times of files after reading
-I [[USER@]HOST:]FILE-NAME  Archive filename to use instead of standard input. Optional USER and HOST specify the user and host
names in case of a remote archive
-L, –dereference  Dereference symbolic links (copy the files
that they point to instead of copying the links).
-R, –owner=[USER][:.][GROUP]  Set the ownership of all files created to the specified USER and/or GROUP

Operation modifiers valid in copy-in and copy-pass modes:

-d, –make-directories  Create leading directories where needed
-m, –preserve-modification-time
Retain previous file modification times when creating files
–no-preserve-owner  Do not change the ownership of the files
–sparse  Write files with large blocks of zeros as sparse
-u, –unconditional  Replace all files unconditionally

-?, –help  give this help list
–usage  give a short usage message
–version  print program version

Mandatory or optional arguments to long options are also mandatory or optional for any corresponding short options.

Report bugs to <[email protected]>.

What is Hadoop ? Facts you must know about Apache Hadoop

Apache hadoop

What Is Hadoop?
Apache Hadoop is an open source software frame work developed by Apache Hadoop Project.
The framework allows distributed data processing spread over a large number of computers.
Hadoop 2.x is the latest version with major changes in its architecture & current release is 2.3.0 , released on 20 February, 2014.

Linux & Unix Date Format Examples

Learn about Linux and Unix date & time formating with the help of simple explanation and added example. Date command in Unix & Linux is used to format date as well as time. First portion of this article covers Date  function and the second portion has the  time function covered.

Php Date Format

Date time formatting in PHP
Many scripts written in php need date and time function . PHP has many predfined date formats and you can also customized it as per your need .
Here are some of the date format examples and additional details for php.

ssh Without Password in Few Simple Steps

How to configure passwordless ssh &sftp access in Unix & Linux systems? Follow these simple steps with examples with a basic troubleshooting section at the end. sftp uses underlaying ssh access for authentication and after you establish passwordless ssh access you will have passwordless sftp access as well.

This a real life example of configuring passwordless access for two users . The user ‘web’ in this case needs a secure password less access to another user james in a server ‘devserver’

Geek Speaks

Geek Speaks – collection of previous geek speaks
SE, HVD, LVD SCSI interfaces
CIDR : Classless Inter-Domain Routing
Priority Paging
Dynamic System Domains

Unix Tutorial – Learn Unix OS Basics to get started

This is a Unix Tutorial where you can learn Unix OS Basics to get started with UNIX and Linux operating systems and covers Unix Directory structure , Unix Commads and Unix Shells