Pdfselect allows to extract pages from a single pdf file or from multiple files and to combine these pages to a new pdf file.
The modus pdfselect
There are two ways to use Pdfselect. The first modus is called pdfselect, and it is applicable, when the source is a single pdf document, which has to be opened in Preview. Clicking then either the button "run pdfselect" or "run pdfselect + open pdf" in Pdfselect's main window, will open a dialogue window where you specify which pages should be extracted by entering the page numbers as a list, e.g., the list
3,7-23,1
entered in a dialogue window, will produce a pdf file containing the pages 3, 7-23, and page 1 in that order. The paper size will be that of the original file. The string "-" will insert all pages and "4-" all pages starting with page 4.
The modus pdfmerge
The second modus can be used in case of a single source file or in case of multiple source files.