qpdf: Add a few more common examples

pages/common/qpdf.md

@@ -2,6 +2,22 @@
 
 > Versatile PDF transformation software.
 
+- Extract a few pages from a pdf into another one:
+
+`qpdf --empty --pages {{input.pdf}} 1,6-8,12 -- {{output.pdf}}`
+
+- Extract pages from multiple pdf files into one:
+
+`qpdf --empty --pages {{file 1.pdf}} 1,6-8 --pages {{file 2.pdf}} 3,4,5 -- {{output.pdf}}`
+
+- Write each group of n pages to a separate output file:
+
+`qpdf --split-pages=n {{input.pdf}} {{page %d.pdf}}`
+
+- Rotate and transform the PDF:
+
+`qpdf --rotate=+90:2,4,6 --rotate=180:7-8 {{input.pdf}} {{output.pdf}}`
+
 - Remove the password from a password protected file:
 
-`qpdf --password={{password}} --decrypt {input_file.pdf}} {{output_file.pdf}}`
+`qpdf --password={{password}} --decrypt {{input.pdf}} {{output.pdf}}`