来自 Postscript 语言参考手册第 3 版。在 6.1.1：
Note: setpagedevice is a page-oriented operator used to control the output process-
ing of one or more pages of a page description. Any call to setpagedevice implicitly
invokes erasepage and initgraphics, and thus must precede the descriptions of the
pages to be affected. If the current device is not a page device, the effect of invoking
setpagedevice is device-dependent.
因此尝试在文本编辑器中打开 PostScript 文件并在第 1 页代码的开头插入“> setpagedevice”并在开头插入“> setpagedevice”的第 2 页代码。如 6.2.3 所述，还可能需要 > 选项：
Duplex boolean A flag determining whether the output is to be printed duplex (on both sides
of the physical medium) or simplex (on one side of the medium only). If this
flag is true, pairs of consecutive page images will be printed on opposite sides
of a single sheet of medium; if false, each page will be printed on a separate
sheet.
On device activation, a duplex device always prints the first page on a new
sheet of medium; on deactivation, it automatically delivers the last sheet of
medium if it has been printed on only one side.
Tumble boolean A flag specifying the relative orientation of page images on opposite sides of a
sheet of medium in duplex output (that is, when Duplex is true). If Tumble is
false, the default user spaces of the two pages are oriented suitably for binding
at the left or right, with vertical (y) coordinates in the two spaces increasing
toward the same edge of the physical medium. If Tumble is true, the default
user spaces are oriented suitably for binding at the top or bottom, with verti-
cal coordinates increasing toward opposite edges of the medium. If Duplex is
false, the Tumble parameter has no effect.
Note that Tumble is defined in terms of default user space—the user space
established by setpagedevice. The orientation of default user space with re-
spect to the medium is determined by the PageSize and Orientation
parameters, possibly altered by the Install procedure. Consistent results are
obtained across all devices that support duplexing, regardless of how the me-
dium moves through the printing mechanism. However, if a page description
alters user space by invoking operators such as rotate, the visual orientation
of the material printed on the page may differ from the orientation of default
user space.
编辑：现在我明白了。除了无法使用我的单面打印机检查双面打印外，我能够修改您将字符串插入后记的方法。 Ghostscript 确实按预期将正确的字符串插入到 %%BeginPageSetup 中：
-c "<</PSPageOptions [ ( (page +1) print) (<</Duplex true>> setpagedevice) ( (page 2+) print) ] /LockDistillerParams true>> setdistillerparams"
第一页和第三页发出页面字符串，我发现 setpagedevice 在页面 +2 的正确位置，所以我希望一切正常。您的第一次尝试非常接近，我也学到了一些东西。
page +1>>showpage, press <return> to continue<<
>>showpage, press <return> to continue<<
page 2+>>showpage, press <return> to continue<<
page +1>>showpage, press <return> to continue<<
>>showpage, press <return> to continue<<
page 2+>>showpage, press <return> to continue<<
page +1>>showpage, press <return> to continue<<