There are now many different pen filters for different devices. These programs differ only in the device-dependent output routines. They share a common vplot interpreter, and most filters make use of common intermediate-level code. This manual entry describes those options that are implemented in the device independent part and thus are common to all pen filters. Though many of these are included mostly for backward compatibility with older versions of vplot, they also add quite a lot of flexibility to the system.
String is an input file containing vplot-format plot commands.
The standard input is also read. Some pen filters may support several related, but not identical, devices. This variable allows you to tell the pen filter the exact device type that you are using. The command line takes precedence. Normally the presence of any options on the command line inhibits self-documentation.