pagespecs follow the syntax:
modulo is the number of pages in each block. The value of modulo should be greater than 0; the default value is 1. The optional mag parameter adjusts the file's magnification by the magnification specified. The magnification and modulo can be specified in reverse order if desired. specs are the page specifications for the pages in each block. The value of the pageno in each spec should be between 0 (for the first page in the block) and modulo-1 (for the last page in each block) inclusive. The optional dimensions xoff and yoff shift the page by the specified (positive) amount. xoff and yoff are in PostScript's points, but may be followed by the units cm or in to convert to centimetres or inches, or the flag w or h to specify as a multiple of the width or height. If the optional minus sign is specified, the page is relative to the end of the document, instead of the start.
If page specs are separated by + the pages will be merged into one page; if they are separated by , they will be on separate pages. If there is only one page specification, with pageno zero, the pageno may be omitted.
The -w option gives the width which is used by the w dimension specifier, and the -h option gives the height which is used by the h dimension specifier. These dimensions are also used (after scaling) to set the clipping path for each page.
To reduce an A3 page to A4 size, the pagespec to use is:
To select all of the odd pages in reverse order, use: