The system runs $HOME/.profile whenever you log in, after it runs /etc/profile. If you change your .profile, the changes don't go into effect until you next log in.

You should use your .profile to do the customizations that you need to do only once, or that you want all shells to inherit. For example, you could:

Note: If you want to create an alias, you should do it in your shell's profile (see ksh's startup file), not in .profile, because the shell doesn't export aliases. If you do set an alias in .profile, the alias is set only in shells that you start as login shells, using the -l option.

For an example of .profile, see the Examples appendix.