To get IP Address of Sun Server

For a normal user (i.e., not 'root') ifconfig isn't in his path, but it's the command.

More specifically: /usr/sbin/ifconfig -a

If we want the IP Address easily, we need some scripting as:

/usr/sbin/ifconfig -a | awk 'BEGIN { count=0; } { if ( $1 ~ /inet/ ) { count++; if( count==2 ) { print $2; } } }'

Modifying file using Vim and awk

In some case, we have to change a big file with the same type of text. We can use vim editor for doing this type of task. Suppose, we have a files as below:

Now for a need, we need to generate delete script from this file contents as below:

For doing so, 

1. we have opened the file using vim editor. vim loglistws.txt

2.Then we have used the below commnads to add double quate around the words : 

   :%s/EJB_Str/"EJB_Str/g

   

Then save the file using :w

   :%s/\.log/\.log"/g

3. Now save the file using :wq!

4. Now we have made a new file form the existing file as:

    cat loglistws.txt | awk '{print "rm ",$9,$10,$11,$12}' > myscriptws.sh

Comparing between two packages

Many times we need to compare between different packages, wars, jars to find out the specific differences. We can use different tools for this purpose i.e pkgdiff, japi-complicance-checker, clirr. Here the process of finding differences has been depicted using the pkgdiff.

1. Download the zipped file from: https://github.com/lvc/pkgdiff/archive/1.7.2.tar.gz
2. Untar the files using the command: tar xvfz somefilename.tar.gz
3. Open the unzip folder.  in this folder make script is available.
4. Install the file using the command:  sudo make install prefix=/usr
5. Now compare the files using:  pkgdiff filename.jar filename_new.jar
6. The above command will provide the result.
7. A report will also be generated in html. We can get the details report from that file.

Archive Redo Log

An Oracle database can run in one of two modes. By default, the database is created in NOARCHIVELOG mode. Oracle Database lets you save filled groups of redo log files to one or more offline destinations using its ARCH process, known collectively as the archived redo log, or more simply the archive log. The process of turning redo log files into archived redo log files is called archiving.

When in NOARCHIVELOG mode the database runs normally, but there is no capacity to perform any type of point in time recovery operations or online backups. Thus, you have to shutdown the database to back it up, and when you recover the database you can only recover it to the point of the last backup. While this might be fine for a development environment, the big corporate types tend to frown when a weeks worth of current production accounting data is lost forever. We can check the status of the archiving mode of a database suing hte following query:

SQL> archive log list;

SQL> select log_mode from v$database;

we can also with the below commnad to find the process:
$ ps -ef|grep -i _arc

To run a command repeatedly in Linux

For many cases, we need to execute the command repeatedly in the shell. We can do it by cron. But in that cat its not feasible to use cron if the interval time is less than 1 min or more. Suppose, we are inclined to get the output like the top command for a specific command. We can do that in the following ways as:

watch Command
# watch free -m [By Default 2 Sec Interval]
# watch -n 10 script.sh [For the interval of 10 Seconds]
Sleep Command:
a) inside For Loop
# for i in {1..10}; do echo -n "This is a test in loop $i "; date ; sleep
b) Inside while Loop
# while true; do echo -n "This is a test of while loop";date ; sleep 5; done