the command line is treated as the filespec of an image to
run, and an attempt is made to invoke it (using F<.Exe> and
the process defaults to expand the filespec) and pass the
-rest of C<exec>'s argument to it as parameters.
+rest of C<exec>'s argument to it as parameters. If the token
+has no file type, and matches a file with null type, then an
+attempt is made to determine whether the file is an executable
+image which should be invoked using C<MCR> or a text file which
+should be passed to DCL as a command procedure.
You can use C<exec> in both ways within the same script, as
long as you call C<fork> and C<exec> in pairs. Perl
using a default type of F<.Exe> and the process defaults, and if
successful, the resulting file is invoked via C<MCR>. This allows you
to invoke an image directly simply by passing the file specification
-to C<system>, a common Unixish idiom. If LIST consists
-of the empty string, C<system> spawns an interactive DCL subprocess,
-in the same fashion as typiing B<SPAWN> at the DCL prompt.
+to C<system>, a common Unixish idiom. If the token has no file type,
+and matches a file with null type, then an attempt is made to
+determine whether the file is an executable image which should be
+invoked using C<MCR> or a text file which should be passed to DCL
+as a command procedure.
+
+If LIST consists of the empty string, C<system> spawns an
+interactive DCL subprocess, in the same fashion as typiing
+B<SPAWN> at the DCL prompt.
+
Perl waits for the subprocess to complete before continuing
execution in the current process. As described in L<perlfunc>,
the return value of C<system> is a fake "status" which follows
=head2 SDBM_File
-SDBM_File works peroperly on VMS. It has, however, one minor
-difference. The database directory file created has a L<.sdbm_dir>
-extension rather than a L<.dir> extension. L<.dir> files are VMS filesystem
+SDBM_File works properly on VMS. It has, however, one minor
+difference. The database directory file created has a F<.sdbm_dir>
+extension rather than a F<.dir> extension. F<.dir> files are VMS filesystem
directory files, and using them for other purposes could cause unacceptable
problems.