To define a temporary value to a shell variable use the command:
The value of this variable will remain set until you exit from this shell. The value of this variable is not exported to other C shells when they are invoked.
To give a lasting value to a shell variable:
1. Use an editor to open your .cshrc (.tcshrc) file and add the line:
2. Save the file and leave the editor.
3. Enter the command:
This adds the value of the shell variable to your shell's present environment. When other C shells are invoked they will also have this variable set.