basic structure; zsh default; no desktop assumed

_custom/.local/lib/pdf_tools.sh

@@ -0,0 +1,8 @@
+#!/bin/zsh
+function pdf_num_pages {
+    gs -q -dNOSAFER -dNODISPLAY -c "($1) (r) file runpdfbegin pdfpagecount = quit"
+}
+
+function pdf_extract_range {
+    yes | gs -q -dBATCH -sOutputFile="$4" -dFirstPage=$2 -dLastPage=$3 -sDEVICE=pdfwrite "$1"
+}