How to set Environment Variable Path in Linux

I am successful in setting Environment variable for JAVA which will move through Control Panel -> System -> Advance -> Environment Variables. But when i follow same way to set the PATH in Redhat Linux it does not allow me to do so is there any other way to set environment variable, please guide me. Thanks to those who helps.

Linux and UNIX: Make sure that the system variables include the directory where the Q replication libraries and executables are installed. The default library path is LIBPATH=SQLLIB/LIB, and the default executable path is PATH=SQLLIB/BIN in the DB2 instance home directory. If you moved the files, update your environment variables to include the new path.

AIX and DB2 Extended Server Edition: Set the EXTSHM environment variable to ON at the source and target databases on AIX, or at the source database only on DB2 Extended Server Edition (if the Q Capture program must connect to multiple database partitions), by entering the following commands:

Code:

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$ export EXTSHM=ON
$ db2set DB2ENVLIST=EXTSHM

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Ensure that the EXTSHM environment variable is set each time you start DB2. Do this by editing the/home/db2inst/sqllib/profile.env file and adding or modifying the line:

Quote:

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DB2ENVLIST='EXTSHM'

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source: IBM.COM

Environment variables are a set of values that can affect the way running processes will behave. It is stored in the shell's environment space.

/bin:/usr/bin:/usr/local/bin

When you enter a command, the shell looks in each of the directories specified in PATH to try to find it. If it can't find the command in any of those directories, you'll see a "Command not found" message.

/home/user/.bash_profile (~/.bash_profile)

Use text editor such as vi to modify or define new environment variable for you, If you decide to put your own programs in a bin directory under your home directory, you'll have to modify the path to include that directory, or the system will never find your programs (unless you happen to be in that directory when you enter the command).

Environment variables are a variable key pair stored in the shell's environment space. This would add the new directory to the existing PATH value. Always a $VARIABLE is substituted with the current value of the variable. Running programs can access the values of environment variables for configuration purposes. Examples of environment variables include:

• PATH : Search for executable files
• SHELL : Your current shell