-in the L<passwd(5)> entry of the user that the command is
-being run as. The command name argument given to the shell begins
-with a `C<->' to tell the shell to run as a login shell. B<sudo>
-attempts to change to that user's home directory before running the
-shell. It also initializes the environment, leaving I<TERM>
-unchanged, setting I<HOME>, I<SHELL>, I<USER>, I<LOGNAME>, and
-I<PATH>, and unsetting all other environment variables. Note that
-because the shell to use is determined before the I<sudoers> file
-is parsed, a I<runas_default> setting in I<sudoers> will specify
-the user to run the shell as but will not affect which shell is
-actually run.
+in the L<passwd(5)> entry of the target user as a login shell. This
+means that login-specific resource files such as C<.profile> or
+C<.login> will be read by the shell. If a command is specified,
+it is passed to the shell for execution. Otherwise, an interactive
+shell is executed. B<sudo> attempts to change to that user's home
+directory before running the shell. It also initializes the
+environment, leaving I<DISPLAY> and I<TERM> unchanged, setting
+I<HOME>, I<SHELL>, I<USER>, I<LOGNAME>, and I<PATH>, as well as
+the contents of F</etc/environment> on Linux and AIX systems.
+All other environment variables are removed.