How to install ANT in Windows

Its soo simple...

Go to

http://code.google.com/p/winant/

and download the latest version and install.

When you install this it not only install Ant but it also installs Ant-contrib

and it too sets all the environment variables for you..!

For all these you only need to know the JAVA_HOME

To find out your Java home open the command prompt and type

echo %JAVA_HOME%

Shell scrips to start and stop background processes in Linux

Here I presents an overview of some useful shell scripts for starting and stopping background process, manually, or by other shells or programmes.

To start and stop background processes, in most situations we need their PID (process ID).

To find out the PID of the process

use the command;

ps 

To show all the processes;

ps -A 

To find out the  PID and the PGID (process group ID) of the processes;

ps -o cmd,pid,pgid

To get the PID for the given process name;

pgrep <process name>

e.g 

pgrep bash

 
To kill the process

To kill the process by process name;

pkill <process name>

e.g. 

pkill java

To kill by PID;

kill -9 <PID>

e.g.

kill -9 12345

To kill by PGID (process group ID);

kill -9 -<PGID>

e.g. if pgid is 9876, then type as;

kill -9 -9876

To kill process by their process name;

pkill <process name>

e.g.

pkill java

Now we'll move in to background processes. These processes seems to useful situations like;

• Other processes want the same terminal to execute them selves.
• When time consuming processes is executed
• Several processes need to be started one after other
• etc

There is a very easy way to do this in Linux. We just need to add '2>&1 &' at the end of the shell command, where the process will start in the background and immediately returns the terminal back to the user.

e.g. 

./server.sh 2>&1 &

./server.sh > server.log 2>&1 &

Note: If you use '2>&1', the script won't return the terminal, until the processing is over.

But when we start and kill processes pragmatically, we encounter a new challenge. We should kill the exact process that we started, and we should not kill some other process!!
To do so, we should keep tack of the PID of the processes we started.

In order to get the PIDs, we can add the following code to the shell script that we are running.
To get the PID of the process that is currently running;

echo $$ > server.pid

Or to get the PID of the process, last started;

echo $! &> server.pid

Well, now we have the PID. Next, we have to kill the processes we stated.
If we only have single processes - which don't have child processes - we can use a command like;

cat server.pid | xargs -i kill -9 {}

This kills all the processes, who's PIDs in the servers.pid.

But sometimes we encounter process trees, in this case when we kill the parent process the child process wont just get killed, but it itself will become a parent. In such situations we should kill the whole process tree.

If you want to view the process tree, you can use the command;

ps f

Or for a detailed view;

pstree

Sometimes in background processes, you encounter problems that the child processes wont get killed even we kill the parent process. Therefore to kill the child processes, you can use two approaches.

1. kill the process tree (recommended)
2. kill the processes which contains the same PGID (this works because in most cases the whole process tree will have the same process group id (PGID))

Killing the process tree using the parent's PID

you can uses that following shell script;

#!/bin/sh
for i in `ps -ef| awk '$3 == '${$1}' { print $2 }'`
do
echo killing $i
kill -9 $i
done
echo killing $1
kill -9 $1

Save this as 'kill-process-tree.sh'

Give executable permission to the script by the command;

chmod 755 kill-process-tree.sh

Then use the command to run the script;

./kill-process-tree.sh

e.g.

./kill-process-tree.sh 7234

Killing the processes which contains the same PGID

First we need to find out the PGID of the given PID of the process;

echo $! |xargs echo | xargs -i ps -o pgid -p {}|xargs echo |awk '{print $2}' > server.pgid

Then to kill the processes with give PGID use the command;

cat server.pid | xargs -i kill -9 -{}

What motivates Open-Source ???

Apache PhotArk M2-incubating released

The Apache PhotArk team is pleased to announce the release of Apache PhotArk M2-incubating.

Apache PhotArk will be a complete open source photo gallery application including a content repository for the images, a display piece, an access control layer, and upload capabilities. The idea is to have a rigid design for the content repository with a very flexible display piece. The images in the content repository will be protected with granular access control.

PhotArk gallery currently allows you define and manage a set of albums hosted local into the content repository and provides a default web UI for album navigation. PhotArk also supports creating and deploying your own photo gallery into Google AppEngine cloud infrastructure.

For full details about the release and to download the distributions please go to:

http://incubator.apache.org/photark/photark-downloads.html

Apache PhotArk welcomes your help. Any contribution, including code, testing, contributions to the documentation, or bug reporting is always appreciated. For more information on how to get involved in
Apache PhotArk visit the website at:

http://incubator.apache.org/photark/

Thank you for your interest in Apache PhotArk!

The Apache PhotArk Team.

Linux/Unix chmod (chmod xxx file)

Here I'm giving a brief explanation on how to changes the permission of a file in Linux/Unix system.

Syntax;

chmod [numeric number] [file]

here [numeric number] is created using the following criteria.

	owner (User who owns the file.)	group (Group that owns the file.)	anybody (Other)
non	0	0	0
read	4	4	4
write	2	2	2
execute	1	1	1

so its easy.

if you want only read by owner;

chmod 400 file

if only executed by others

chmod 001 file

if read/write by the owner and only read by everyone else

chmod (4+2)(4)(4)  file

which is;

chmod 644 file

With this if all need executable rights

chmod (4+2+1)(4+1)(4+1)  file

that's it;

chmod 755 file

This can also be calculated in a more professional way.

when we are checking the permissions of files using "ls -l" command in the terminal we get a results which looks like "- rwx r-x r-- file ".

this can be interpreted as;

- rwx r-x r-- file 

--111 101 100

here;

    r  read

    w  write

    x executable

    - non

Where now when we convert each set binary digits to decimal,

Binary Decimal 000 0 001 1 010 2 011 3

Binary Decimal 100 4 101 5 110 6 111 7

We get the numeric values we wonted. In this case its 754

So we have to use the command.

chmod 754 file