Syntax

     A perl script consists of a  sequence  of  declarations  and
     commands.   The only things that need to be declared in perl
     are report formats and subroutines.  See the sections  below
     for  more information on those declarations.  All uninitial-
     ized user-created objects are assumed to start with  a  null
     or 0 value until they are defined by some explicit operation
     such as assignment.  The sequence of  commands  is  executed
     just once, unlike in sed and awk scripts, where the sequence
     of commands is executed for each  input  line.   While  this
     means  that  you must explicitly loop over the lines of your
     input file (or files), it also means you have much more con-
     trol  over  which files and which lines you look at.  (Actu-
     ally, I'm lying--it is possible to do an implicit loop  with
     either the -n or -p switch.)

     A declaration can be put anywhere a command can, but has  no
     effect   on   the  execution  of  the  primary  sequence  of
     commands--declarations all  take  effect  at  compile  time.
     Typically  all  the declarations are put at the beginning or
     the end of the script.

     Perl is, for the most part, a free-form language.  (The only
     exception to this is format declarations, for fairly obvious
     reasons.)  Comments are indicated by the  #  character,  and
     extend  to the end of the line.  If you attempt to use /* */
     C comments, it will be interpreted  either  as  division  or
     pattern  matching,  depending  on  the context.  So don't do
     that.