The .logout file contains commands and programs that are executed when you log out. For example, the .logout file may contain the clear command, which clears the screen upon logout. Variables are strings that have corresponding values. Variables begin with a letter, and may contain letters, digits, and underscores. Strings containing blank spaces are not recognized as variables.
Some variables appear under both categories.
Shell Variables Shell variables are specific to the C shell and are typically set in the .cshrc file. Shell variables that you create or change on the command line apply only to the current shell. Shell variables created or changed in the .cshrc file are executed for all C shells that are invoked. By convention, shell variables are written in lowercase letters. Below are examples of shell variables.