UNIX Command: cd

Changes the directory

SYNOPSIS
cs [DIRECTORY]

DIRECTORY - Name of the directory you want to enter
cd .. - Go back from current directory

Examples
cd
This will move the current directory to home directory

cd../../
This will move current directory to two step back directory

cd ../root/misc
This will move current directory to one step back then the /root/misc directory

cd misc
This will move current directory to misc directory if available

UNIX Command: chmod

Changes the file or directory permission to a user, group or others

Synopsis
chmod [OPTION] .. MODE[,MODE] .. FILE ..
chmod [OPTION] .. OCTAL-MODE FILE ..
chmod [OPTION] .. --reference=RFILE FILE ..

Options
-c, --changes
like verbose but report only when a change is made
-f, --silent, --quiet
Suppress most error messages
-v, --verbose
Output a diagnostic for every file processed
--reference=RFILE
Use RFILE's mode instead of MODE values
-R, --recursive
Change files and directories recursively
--help
Display this help and exit
--version
Output version information and exit

Permissions
u - User who owns the file.
g - Group that owns the file.
o - Other.
a - All.
r - Read the file.
w - Write or edit the file.
x - Execute or run the file as a program.

Numeric Permissions:
CHMOD can also to attributed by using Numeric Permissions:

400 read by owner
040 read by group
004 read by anybody (other)
200 write by owner
020 write by group
002 write by anybody
100 execute by owner
010 execute by group
001 execute by anybody


Example
chmod 644 file.txt
This gives the file file.txt read/write by the owner and only read by everyone else (-rw-r--r--).

chmod 755 file.txt
Gives all the rights but the capability for anyone to edit tile.txt (-rwxr-xr-x).

chmod 666 file.txt
Gives read and right permission to everyone.

UNIX Command: cat

cat is one of the most flexible command of UNIX. It can be used to create, concat and view file.

Sysnopsis
cat [OPTION] [FILE]
DESCRIPTION

Example: Create a new file address
cat >address
Sharif R#67, Dhaka -1207
Mizan R#123, Rajshahi


Example: To view the file addreaa
cat address

Example: Add text to addreaa
cat >>address
Shaila Godagari, Rajshahi

Example: To concat a file temp to another
cat temp>>address

Options
-e Print $ at the end of each line. This option must be used with -v.
-s Suppress messages pertaining to files that do not exist.
-t Display tab as ^I and form feed as ^L. This option must be used with -v.
-u Print output as unbuffered.
-v Display control characters and nonprinting characters

UNIX Common Shell Commands

Here are the commonly used UNIX shell commands

balance:
Lists remaining money in account

cat > filename
Easy way to create a file.

cat file1 >> file2
Concatenates file1 on the end of file2

cd newdir
Change current directory to "newdir"

correct filename
Corrects spelling of text in "file"

cp filename newfilename
Makes a copy of a file

date
Gives date and time

finger
Gives names & account numbers of current logins

frm
Shows who mail is from

from
shows who mail is from

help
Tells about on-line help

logout
When you are finished working

look [string]
Finds all words that match string

ls
Lists contents of current directory

mail
To read mail

mail usename
Sends mail to "user"

mkdir directory.name
Makes a directory

more filename
Prints file on screen one page at a time

mv file1 file2
Changes name of file1 to file2

passwd
Changes password

pwd
"print working directory" - Shows working directory name

quota -v
Shows account disk-space use

rm
Removes a file

tset [type]
Tells computer what type of terminal you are using

uptime
Shows number of users and load on machine

vi filename
Creates or opens file for editing

webster [word]
Gives definition, pronunciation and etymology of "word"

Java : JTable example

Here is a simple java JTable example

import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Vector;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.ScrollPaneLayout;

public class MyFrame extends JFrame implements ActionListener{
JButton button = new JButton("Press me");
JScrollPane scrollpane = null;

Vector c = new Vector();
Vector r = new Vector();
Vector rs = new Vector();
JTable table = null;
public MyFrame() {
c.add("Name");
c.add("Age");
r.add("Sharif");
r.add("28");
rs.add(r);
r.add("Shaila");
r.add("23");
rs.add(r);
table = new JTable(rs,c);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 400, 400);
setLayout(new GridLayout(0,1));
scrollpane = new JScrollPane(table);
}
public void init(){
button.addActionListener(this);
getContentPane().add(button);
getContentPane().add(scrollpane);
setVisible(true);
}
public static void main(String args[]) {
MyFrame frame = new MyFrame();
frame.init();
}

public void actionPerformed(ActionEvent ac) {
System.out.println(ac.getSource());

}
}