Setting Environment and Shell Variables

Environment variables and shell variables (parameters) are set in the .profile and ENV files. (The ENV file is often, but not always, .kshrc.) These variables create part of the environment in which you work, such as your prompt string (PS1). Environment variables are shell parameters that are global and used by your shell to create a special environment for subshells and any commands you may invoke. This environment is active until you logoff. These global (or exported) environment variables can be seen and used by subshells and other subprocesses. Shell variables are shell parameters that are local to your login shell and not passed on to any subprocesses or subshells.