Programming with the UNIX system shell

Modifying your login environment

The UNIX system lets you modify your login environment in several ways. For example, users frequently want to change the default values of the erase and line kill characters, <CTRL-h> and ``@'', respectively.

When you log in, the shell first examines a file in your login directory named .profile (pronounced ``dot profile''). This file contains commands that control your shell environment.

Because the .profile is a shell script, it can be edited and changed to suit your needs. On some systems you can edit this file yourself, whereas on others, the system administrator must do this for you. To see whether you have a .profile in your home directory, type:

   ls -al $HOME

If you can edit the file yourself, you may want to be cautious the first few times. Before making any changes to your .profile, make a copy of it in another file called safe.profile. Type:

   cp .profile safe.profile

You can add commands to your .profile just as you add commands to any other shell program. You can also set some terminal options with the stty command, and set some shell variables.