Plot inequalities

Teaching my son howto determine domain for inequalities and plot.

x^3 -5x^2 -9x +45 <= 0

so (x+3)(x-3)(x-5) <=0

so critical points are 3,-3 and 5.

Next plot graph using derivatives.
1st derivative is 3x^2 -10x -9 which is zero for x approx 4 or x approx -2/3.
2nd drivative is -ve for x=4 and +ve for x=2/3.
Plot and you will find 2 regions where graph is in 3rd and 4th quadrant (y is -ve or <0)
1st region where y<=0 is x between 3 and 5 and 2nd region where y<=0 is x< -3. and these are the two answers

Knoppix on USB

You’ll need the following to create a Portable Knoppix:

• 1GB or Larger USB Flash Pen Drive (fat32 formatted)
• Windows PC to perform the conversion (XP or Vista)
• fixkp2.exe Download fixkp2.exe and run, a USB-Knoppix folder is created
• Download the Knoppix Linux ISO and move it to the USB-Knoppix folder
• Click fixkp2.bat from the USB-Knoppix folder and follow the onscreen instructions
• Reboot your PC and set your system BIOS or Boot Menu to boot from the USB device, save your changes and reboot
  Upon reboot, you should have a successful launch of Knoppix Linux from your USB memory stick.

How to make a Damn Small Linux USB Flash Drive:

• Download and run Dp.exe, a Dp folder is created (It is on Athena, let me know if you need it)
• Download the dsl-embedded.zip and move it to the Dp folder Click Dp.bat from the Dp folder and follow the onscreen instructions
• Once the script has finished, reboot your computer and set your system BIOS or Boot Menu to boot from the USB device
• On Dell Latitude 610, I had to use the following boot options: dsl acpi=off vga=normal fb1024x768 toram
• Type "sudo [command]" in a terminal window to run a single command with root privileges. This is generally considered the best idea. To get a root shell, type "sudo su".

• If running using qemu on windows, modify the startup script to
• START .\qemu.exe -L . -no-kqemu -m 128 -localtime -soundhw es1370 -kernel linux24 -initrd minirt24.gz -hda KNOPPIX -append "qemu vga=791 quiet noscsi nousb nofirewire atapicd noideraid noacpi acpi=off noapm noagp ide1=noprobe ide2=noprobe nomce frugal"

Reverse Engineer DDL to an ERD

So you always wanted to get a graphical view of the hundreds of tables in Oracle. Given below is the outline of the steps.


Generate the DDL from Oracle using the metadata packages.

SQL>select 'select dbms_metadata.get_ddl(''TABLE'',',''''table_name''''') from dual;' from user_tables;

select dbms_metadata.get_ddl('TABLE','ACCOUNT') from dual;
select dbms_metadata.get_ddl('TABLE','CHANNEL_DIM') from dual;
select dbms_metadata.get_ddl('TABLE','CUSTOMER_DIM') from dual;
select dbms_metadata.get_ddl('TABLE','PRICE_FACT') from dual;


Spool,Execute,Spool,Execute and obtain the DDL into a file for example tables.lst

Created a Perl Program to parse this DDL file and create an output DOT file that will be used as input by the AT&T provided Graphviz utility. This utility can be downloaded from GraphViz

The layout of the DOT file generated is provided here

Take this file DOT file and use the dot utility that you downloaded from GraphViz
From the DOS prompt run.

c:\type input.dot dot -Tpng > output.png

Features of the perl program:

Prints * next to col name to indicate a Mandatory field
Prints # next to col name to indicate a Primary Key
Run in verbose mode to include the column size in the output image
Change the color and font size

SSH and RSA Auth using Putty and MAC

To allow access to a remote system for a given identity place the public key in your ~/.ssh/authorized_keys file on that remote system. All keys listed in that file are allowed access.

Say you want to connect from your Mac to the Linux Server (Athena) as root using RSA Key Authentication. On Mac under the ~ataran/.ssh you need to do a ssh-keygen -t rsa and create the pub, priv keys with a secret passphrase. Then take this pub key from the Mac and add it to the ~root/.ssh/authorized_keys. Then from MAC you can do ssh root@athena and you will be prompted to enter the secret passphrase.

Now back to the other question of how to use Putty-based RSA public-key with OpenSSH server on Athena. The public-key generated by Puttygen is not compatible with the one generated by OpenSSH. However, you can manually modify the Putty-based public key before appending it to authorized_keys file on Athena.

• ssh to your Linux server using the loginid and password


• chmod 700 ~/.ssh folder


• chmod 600 ~/.ssh/authorized_keys


• ssh-keygen -t dsa
  (or rsa; accept the file names it wants to use, enter a strong passphrase)
• Open Puttygen (Putty Key Generator), click Generate button and move the mouse cursor randomly within the key section/frame to create the key with default settings (e.g. SSH-2 RSA of 1024 bits).
• When the key generation completes, create a strong passphrase in the text box provided.
• Then, click save Public Key and Save Private Key button, one after another, to save the pair of key to local hard disk.
• Transfer the Puttygen-created public key to the linux server. Let’s say this public key is only meant for root user account, append the contents of this public key in ~root/.ssh/authorized_keys file.
• On the Linux Server open the authorized_keys file with vi editor and delete the lines initial with four dash and “Comment”. Join the remain lines into one, single line. Initial that single line with ssh-rsa keyword (a space at the end).
• NOW change your putty settings under "connection > SSH > auth" to use privatekey.ppk
• NOW try and connect using Putty SSH (root@athena) and enter the passphrase when prompted
  

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Sed & Awk

Click here for an excellent article on Sed and Awk on liners that I found on the web. I will post another article for Perl one liners

Secure MySQL Install

Can be used for the Install on Synology or Any Windows or Unix based Install

• To restart mysql on Synology /usr/syno/etc/rc.d/S21mysql.sh
• mysqladmin -u mysql -p shutdown
• To restartOn Synology WebGUI, System->Restore defaults->Reset MYSQL Database Password will reset password for MYSQL databaseInstalled phpMyAdmin
• To Connect mysql -h host -u user -p myout.lst
• For admin mysqladmin -u mysql -p pingstatusshutdown
• show global status or show grants
• connect with mysql using user=root and verify user table in mysql database. Update password using phpmyadmin. Note if you login using user=mysql you wont see the user table. Do not ever give anyone (except MySQL root accounts) access to the user table in the mysql database. Set passwords to all root accounts using password() function or phpmyadmin
• mysql_install_db creates one root account (superuser) for connection from localhost only. Two anonymous-user accounts are created each with empty username and these anonymous accounts have no password so abobe can connect to mysql.On Windows, one anonymous account is for connections from the local host. It has no global privileges. (Before MySQL 5.1.16, it has all global privileges, just like the root accounts.) The other is for connections from any host and has all privileges for the test database and for other databases with names that start with test
• mysql> select host,user,password from user
  localhost root *7D2ABFF56C15D67445082FBB4ACD2DCD26C0ED57
  Athena root *7D2ABFF56C15D67445082FBB4ACD2DCD26C0ED57
  Athena *7D2ABFF56C15D67445082FBB4ACD2DCD26C0ED57
  localhost *7D2ABFF56C15D67445082FBB4ACD2DCD26C0ED57
  localhost scott *F2F68D0BB27A773C1D944270E5FAFED515A3FA40
• shell> mysql -u rootmysql> SET PASSWORD FOR ''@'localhost' = PASSWORD('newpwd');
  mysql> SET PASSWORD FOR ''@'%' = PASSWORD('newpwd');
  OR
  shell> mysqladmin -u root password "newpwd"
  shell> mysqladmin -u root -h host_name password "newpwd"
  OR
  shell> mysql -u rootmysql> UPDATE mysql.user SET Password = PASSWORD('newpwd')
  -> WHERE User = 'root';mysql> FLUSH PRIVILEGES;
  
• That account allows anonymous access but has full privileges, so removing it improves security. If you prefer to remove the anonymous accounts instead, do so as follows:
  shell> mysql -u root
  mysql> DROP USER '';
  DROP USER ''@'localhost';
• Note [mysqld]user=mysql in my.cnf shows that mysqld deamon runs as mysql user and not root
• Coming Up-> howto secure phpMyAdmin and Enable Remote Access via open Port

Blueberry Snack Cake

Ingredients
½ cup(4 oz) butter
¾ cup(6oz) sugar
2 eggs
1 tsp vanilla extact
1 cup flour
1 tsp baking powder
¼ tsp baking soda
¼ tsp salt
½ cup sour-cream
½ cup brown sugar
1 tsp cinnamon
1 cup chopped pecans
1 cup blueberries

• Preheat oven to 350°F. Grease 9'' square pan with solid veg shorting and dust with flour, or use pan spray
• Place butter and sugar in a large mixing bowl, cream until light and fluffy, add eggs and vanilla. Beat
• Toss flour, baking powder, baking soda, and salt with a task. Add alternately with sour-cream to cream mixture. Mix until smooth. Toss brown sugar, cinnamon, and nuts together.
• Pour half the batter into prepared pan. Mix blueberries and ½ the brown sugar cinnamon and batter. Top with other half of nut mixture. Bake 30-40 minutes or until toothpick comes out clean.

Samba share from MAC over WAN

Setup loopback adapter on MAC using command below and then use SSH Port forwarding.

sudo ifconfig lo0 10.0.0.1
sudo ssh -L 10.0.0.1:139:192.168.1.4:139 root@staran.webhop.net

Enable port 22 on Router and forward WAN traffic to 192.168.1.1. Note that the destination host is 192.168.1.4 and not 192.168.1.1.

Setup Network Printer from MAC using CUPS

fixes the not authorized problem
Have a print server running on my Synology server. Need to print from a MAC running OS X.

Log in to cups via the browser using http://localhost:631 on the Mac.
Choose add printer, give the printer a name and location, choose Windows printer via Samba, and as device url use: smb://user:password@ip-adress/usbprinter.

User and password being valid credentials for the Synology device. I used my admin account for this, with the corresponding password.

(I prior installed the latest HP printer drivers (ver. 4.0), but I don't know if this is necessary)

Test from Email

Today we are getting our kitchen cabinet work almost completed. Awesome job done by one hardworking contractor.

Test again

Testing out features of Blogger.

Launch

This is a first page My domain. Check it out