Three ways to configure Linux environment variables

1. Modify the/etc/profile file

This approach is recommended if your computer is used only as a development, because all user shells have the right to use these environment variables, which can pose a security issue for the system.
• Open/etc/profile with a text editor
• At the end of the profile file, add:

Export java_home=/usr/share/jdk1.6.0_14
Export path= $JAVA _home/bin: $PATH
Export classpath=.: $JAVA _home/lib/dt.jar: $JAVA _home/lib/tools.jar

• Re-login

2. Modify the. bash_profile file

This method is more secure, it can control the use of these environment variable permissions to the user level, if you need to give a user permissions to use these environment variables, you only need to modify their personal user home directory of the. bash_profile file on it.
• Open the. bash_profile file in the user directory with a text editor
• At the end of the. bash_profile file, add:

Export java_home=/usr/share/jdk1.6.0_14
Export path= $JAVA _home/bin: $PATH
Export classpath=.: $JAVA _home/lib/dt.jar: $JAVA _home/lib/tools.jar

• Re-login

3. Set variables directly under the shell
Do not support the use of this method, because the shell, your settings are invalid, so this method is only temporary use, and later to use the time to reset, more trouble.
Simply execute the following command at the shell Terminal:
Export java_home=/usr/share/jdk1.6.0_14
Export path= $JAVA _home/bin: $PATH
Export classpath=.: $JAVA _home/lib/dt.jar: $JAVA _home/lib/tools.jar

Java-version

Three ways to configure Linux environment variables