Summary
Now that you have completed this chapter, you should have a firm understanding of the following:

When a user logs in to a UNIX system, several initialization files are read and processed. These files contain settings for variables that customize the user's environment. There are two types of initialization files: system-wide and user-specific. The etc/profile file is the system-wide initialization file that affects all users. It is created when the operating system is installed and can be edited and customized by a system administrator. The /etc/profile file can perform the following:

  • Exports Environment Variables
  • Exports PATH for Default Command Path
  • Sets TERM Variable Default Terminal Type
  • Displays Contents of /etc/motd File
  • Sets Default File Creation Permissions
  • Checks for Mail

The Korn shell uses two additional user-specific initialization files that are kept in the user's home directory: .profile and .kshrc (Korn shell run control). The C shell potentially uses three user-specific files: .login, .cshrc (C shell run control) and .log out. These user-specific files are read after /etc/profile to provide additional customization for the user's environment. They can perform some or all of the following:

  • Set Default Prompt
  • Define Default Printer
  • Set Default Permissions
  • Set Default Terminal
  • Set New Mail Location
  • Set Noclobber
  • Set Command Path
  • Define Custom commands

Common Desktop Environment (CDE) users have a special file called .dtprofile (desktop profile) that is read to provide settings for the graphical desktop and windowing environment.