All About GIT

GIT

Introduction:

[Phrase from man page of git] Git is a fast, scalable, distributed revision control system with an unusually rich command set that provides both high-level operations and full access to internals.

Before you start with git you must know few terminologies regarding revision control system.

Revision Control Systems (in short)

Revision control system is a part of software configuration management. This manages project data such as documents, programs, releases with revision numbers, tags and branches. In practical, suppose you are a member of team of 20 people developing a product and as per each team members responsibility they keep writing their programs and documents, in that few programs and documents are shared and few are dependent. In this case it will be very difficult to keep a track of entire development process and there will be much likely cases in which developers may lose their codes or documents and many times they straight away fall in rework.

TBD….

Samsung S3 and Galaxy Grand I9082 short comparison

It seems that Galaxy Grand is good option in 17-18 thousand. Has good features in comparison with S3 but still S3 is more powerful in processing and has more internal memory plus 2 more sensors than galaxy grand.

In short, summary:

Features	S3	Grand GT-I9082	Remarks
Camera	8.0 megapixels back-side illuminated sensor LED flash HD video (1080p) at 30 frames/s Aperture f/2.6 Autofocus Zero shutter lag Simultaneous HD video and image recording Smile and face detection Image stabilization[6][9]	8 MP 1080p LED flash Full HD Video Recording @ 30fps with auto-focus Self-timer Panorama Smile Shot and Face detection Stop motion image stabilizer	Both are almost same
Camera Modes	Single Burst Mode HDR Smile Shot Beauty Panorama Cartoon Share Shot Buddy Photo Share	Single Smile Shot HDR Panorama	S3 is rich in camera click modes
Internal Memory	16 GB	8 GB	more memory is good so you can store more data and install more apps. Usually with 8 GB internal memory sometimes adding more high end graphics apps slow down the performance
RAM	1 GB	1 GB
CPU	1.4 GHz quad-core Cortex-A9	1.2 GHz Cortex-A9 dual-core
Screen Size	4.8 inches	5 inches
Price	28000 - 27000 INR	17000 - 18000 INR

If its feasible and possible for you in terms of budget then I’d suggest go for S3 J so at list for 2 years you don’t have to worry about new emerging technologies.

Daily used Linux/Unix commands

Command to list latest modified file from parent directory

ls –lRrta

Options:

-l for long listing

-R for recursive

-r for reverse listing

-t for sorting on modified time

-a for listing all including hidden files

Similar command on windows is: dir /N /S

Command to find a file from given path

find -name -print

e.g.

# find /etc -name "1000-gnu.java.security.provider.Gnu" -print

/etc/java/security/security.d/1000-gnu.java.security.provider.Gnu

Command to find a text by searching recursively entire directory contents

find -type f -print | xargs grep "text to search"

e.g.

# find DOWNLOADS/iotop-0.5/ -type f -print | xargs grep "import struct"

DOWNLOADS/iotop-0.5/build/lib/iotop/netlink.py:import struct

DOWNLOADS/iotop-0.5/build/lib/iotop/genetlink.py:import struct

DOWNLOADS/iotop-0.5/build/lib/iotop/data.py:import struct

DOWNLOADS/iotop-0.5/iotop/netlink.py:import struct

DOWNLOADS/iotop-0.5/iotop/genetlink.py:import struct

DOWNLOADS/iotop-0.5/iotop/data.py:import struct

Check directory existence recursively

find -type d -name "directory name to find" -print

e.g.

# find /exported -type d -name "iotop" -print

/exported/DOWNLOADS/iotop-0.5/build/lib/iotop

/exported/DOWNLOADS/iotop-0.5/iotop

 

Difference between grep, egrep and fgrep

gerp Search a Pa tern from current directory.

egrep (grep -E in linux) is extended grep where additional regular expression metacharacters have been added like +, ?, | and ().

fgrep (grep -F in linux) is fixed or fast grep and behaves as grep but does not recognise any regular expression metacharacters as being special.

Upgrading JAVA in RedHat Linux 64 bit platform

1.      Download the binary

wget http://download.oracle.com/otn-pub/java/jdk/6u38-b05/jre-6u38-linux-x64.bin

2.      Run the binary via SHELL to install it.

chmod +x jre-6u38-linux-x64.bin

./jre-6u38-linux-x64.bin

This will create a directory of name 'jre1.6.0_38' Move this directory to /usr/java

3.      Verify the installation

cd /usr/java/jre1.6.0_38/

./java -version

java version "1.6.0_38"

Java(TM) SE Runtime Environment (build 1.6.0_38-b05)

Java HotSpot(TM) 64-Bit Server VM (build 20.13-b02, mixed mode)

4.      Configure the new upgraded java environment

/usr/sbin/alternatives --install /usr/bin/java java /usr/java/jre1.6.0_38/bin/java 1

'1' indicates the priority

/usr/sbin/alternatives --config java

There are 3 programs which provide 'java'.

Selection    Command

-----------------------------------------------

*+ 1           /usr/lib/jvm/jre-1.4.2-gcj/bin/java

2           /usr/java/jre1.6.0_38/bin/java

Enter to keep the current selection[+], or type selection number: 2

5.      Verify the environment

java -version

java version "1.6.0_38"

Java(TM) SE Runtime Environment (build 1.6.0_38-b05)

Java HotSpot(TM) 64-Bit Server VM (build 20.13-b02, mixed mode)

apache-tomcat configuration on linux

Simple steps to configure apache-tomcat server

1. Download apache-tomcat binary tarball from http://tomcat.apache.org/
2. Copy the tarball to a specified location where you want to keep these tomcat installable. In my case   /opt or /usr/rakesh
3. Untar the tarball and rename it as apache-tomcat 

# tar -xvzf apache-tomcat-7.0.32.tar.gz

# mv apache-tomcat-7.0.32 apache-tomcat

4. Open server.xml

# vim apache-tomcat/conf/server.xml

edit line   

# if you wish to keep default port then keep the same else change it to any like

5. Open startup.sh and add JRE_HOME path

# vim apache-tomcat/bin/startup.sh

add following line (set JRE_HOME/JAVA_HOME paths) :

export JRE_HOME=

6. Execute startup.sh to start tomcat server

apache-tomcat/bin/startup.sh

This command will produce following output

 Using CATALINA_BASE:   /opt/apache-tomcat

 Using CATALINA_HOME:   /opt/apache-tomcat

 Using CATALINA_TMPDIR: /opt/apache-tomcat/temp

 Using JRE_HOME:        /usr/lib/jvm/java-1.6.0-openjdk-1.6.0.0.x86_64/jre

 Using CLASSPATH:       /opt/apache-tomcat/bin/bootstrap.jar:/opt/apache-tomcat/bin/tomcat-juli.jar   

7. Open a web browser and type your host's fully qualified domain name and a port number:

http://aspiration.com:8880

OR

http://localhost:8880

This will open the tomcat welcome page.